PGA West Signature - The Villas TR 36537 (Building 2-Plex, 3-Plex, & 4-Plex) Geotechnical UpdateGEOCON
W E S T, I N C.
GEOTECHNICAL ■ ENVIRONMENTAL ■
Project No. T2572-22-01
January 8, 2014
California West Communities
5927 Priestly Drive, Suite 110
Carlsbad, California 92008
Attention: Mr. Mike Lake
Subject: 2013 CBC SEISMIC DESIGN PARAMETERS
PGA WEST, TRACT 36537
LA QUINTA, CALIFORNIA
M A T E R I A L S 0
CITY OF LA QUINTA
BUILDING & SAFETY DEPT.
APPROVE®
FOR CONSTRUCTION
DATE
Reference: Geotechnical Update and Grading Plan Review, PGA West Tract 36537, La Quinta,
California, by Geocon West, Inc., dated December 20, 2013.
Dear Mr. Lake:
At your request, we are providing seismic design parameters in accordance with the 2013 California
Building Code requirements. Recommendations presented in our referenced geotechnical report remain
applicable to the site.
Seismic Design Criteria
We used the computer program U.S. Seismic Design Maps, provided by the USGS. Table 1 summarizes
site -specific design criteria obtained from the 2013 California Building Code (CBC; Based on the 2012
International Building Code [IBC] and ASCE 7-10), Chapter 16 Structural Design, Section 1613
Earthquake Loads. The short spectral response uses a period of 0.2 second. The building structure and
cements should be designed using a Site Class D. We evaluated the Site Class based on the
y� pcussion in Section 1613.3.2 of the 2013 CBC and Table 20.3-1 of ASCE 7-10. The values presented in
Table 1 are for the risk -targeted maximum considered earthquake (MCER).
WV1_
CpM
TABLE 1
2013 CBC SEISMIC DESIGN PARAMETERS
Parameter
Value
2013 CBC Reference
Site Class
D
Section 1613.3.2
NICER Ground Motion Spectral Response
1.500g
Figure 1613.3.1(1)
. Acceleration — Class B (short), Ss
NICER Ground Motion Spectral Response
0.615g
Figure 1613.3.1(2)
Acceleration — Class B (1 sec), Si
40-004 Cook Street #4 0 Palm Desert, California 92211 0 Telephone 760.579.9926 0 bottiato@geoconinc.com
Site Coefficient, FA
1.0
Table 1613.3.3(1)
Site Coefficient, Fv
1.5
Table 1613.3.3(2)
Site Class Modified NICER Spectral Response
1.500g
Section 1613.3.3 (Eqn 16-37)
Acceleration (short), SMs
Site Class Modified MCER Spectral Response
0.922g
Section 1613.3.3 (Eqn 16-38)
Acceleration (I sec), SM,
5% Damped Design
1.000g
Section 1613.3.4 (Eqn 16-39)
Spectral Response Acceleration (short), Sns
5% Damped Design
0.615g
Section 1613.3.4 (Eqn 16-40)
Spectral Response Acceleration (1 sec), Sp,
Table 2 presents additional seismic design parameters for projects located in Seismic Design Categories
of D through F in accordance with ASCE 7-10 for the mapped maximum considered geometric mean
(MCEG).
TABLE 2
2013 CBC SITE ACCELERATION DESIGN PARAMETERS
Parameter
Value
ASCE 7-10 Reference
Mapped MCEG Peak Ground Acceleration,
0.538g
Figure 22-7
PGA
Site Coefficient, FPGA
1.000
Table 11.8-1
Site Class Modified MCEG Peak Ground
0.538g
Section 11.8.3 (Eqn 11.8-1)
Acceleration, PGAM
Conformance to the criteria in Tables 1 and 2 for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur if a large
earthquake occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since
such design may be economically, prohibitive.
Updated Seismic Lateral Earth Pressure
Given the updated seismic design criteria, the proposed retaining walls should be designed with the
following revised seismic lateral pressure added to the active pressure. The seismic load exerted on the
wall should be a triangular distribution with a pressure of 14H (where H is the height of the wall, in feet,
resulting in pounds per square foot [psfJ) exerted at the top of the wall and zero at the base of the wall.
We used the Site Class Modified Peak Ground Acceleration (PGAM) of 0.538g calculated from the 2013
California Building Code and applied a pseudo -static coefficient of 0.33.
Project No. T2572-22-01 -2- January 8, 2014
If you have any questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON WEST, INC.
Chet E. Robinson
GE 2890
LAB:CER:JT:lb
O'epOFES
RO
No.2@gp
Distribution: Addressee (email)
Project No. T2572-22-01 - 3 - January 8, 2014
63
GEOTECHNICAL UPDATE AND
GRADING PLAN REVIEW
PGA WEST, TRACT 36537
LA QUINTA, CALIFORNIA
APR 15 2014
CITY OF LA QUINTA
COMMUNITY DEVELOPMENT
PREPARED FOR
CALIFORNIA WEST COMMUNITIES
CARLSBAD, CALIFORNIA
DECEMBER 20, 2013
PROJECT NO. T2572-22-01
1k
t GE V V ON
W Es T, I N C.
GEOTECHNICAL ■ ENVIRONMENTAL ■
Project No. T2572-22-01
December 20, 2013
Is California West Communities
5927 Priestly Drive, Suite 110
Carlsbad, California 92008
Attention: Mr. Mike Lake
MATERIALS (10)
REC;EIVtD
JUN 2 7 2014
CITY OF LA QUINTA
COMMUNITY DEVELOPMENT
Subject: GEOTECHNICAL UPDATE AND GRADING PLAN REVIEW
PGA WEST, TRACT 36537
LA QUINTA, CALIFORNIA
Dear Mr. Lake:
In accordance with your authorization, we herein submit the results of our geotechnical update and
grading plan review for the subject residential development. The accompanying report presents our
findings, conclusions and recommendations pertaining to the geotechnical aspects of the proposed
residential development with respect to the project grading plans prepared by MDS Consulting dated
December 18, 2013. The study also includes an evaluation of the geologic units and geologic hazards.
Based on the results of this study, it is our opinion the site is considered suitable for the proposed
development provided the recommendations of this report are followed.
This document also transfers the Geotechnical Consultant of Record on the subject project from
Sladden Engineering to Geocon West, Inc. The design team should be informed immediately of this
change. As of the date of this letter, Geocon West, Inc. will be providing all necessary geotechnical
consultation, plan review, design recommendations, inspection and testing services for this project.
Should you have any questions regarding this report, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCONWEST, INC.
�CEG 2316 ~w
LAB:CER:JH
(email) Addressee
Chet E. Robinson
GE 2890
40-004 Cook Street #4 ■ Palm Desert, Colifornio 92211 ■ Telephone 760.579.9926 ■ bottiatoOgeoconinc.com
5�
TABLE OF CONTENTS
PURPOSEAND SCOPE...................................................................................................................... 1
SITE AND PROJECT DESCRIPTION................................................................................................ 1
3. GEOLOGIC SETTING......................................................................................................................... 2
4. GEOLOGIC MATERIALS.................................................................................................................. 3
4.1 General........................................................................................................................................3
4.2 Compacted Fill(Qcf).................................................................................................................. 3
4.3 Undocumented Fill (Qudf)......................................................................................................... 4
4.4 Older Alluvium (Qal)................................................................................................................. 4
GEOLOGICSTRUCTURE..................................................................................................................4
6. GROUNDWATER............................................................................................................................... 4
GEOLOGICHAZARDS...................................................................................................................... 5
7.1 Seismic Hazard Analysis............................................................................................................ 5
7.2 Liquefaction................................................................................................................................7
7.3 Expansive Soil............................................................................................................................7
7.4 Landslides...................................................................................................................................7
7.5 Slope Stability.............................................................................................................................7
7.6 Tsunamis and Seiches................................................................................................................. 8
8. CONCLUSIONS AND RECOMMENDATIONS................................................................................9
8.1
General........................................................................................................................................9
8.2
Soil Characteristics.....................................................................................................................9
8.3
Seismic Design Criteria............................................................................................................
11
8.4
Grading.....................................................................................................................................12
8.5
Earthwork Grading Factors.......................................................................................................
14
8.6
Settlement of Proposed Fill......................................................................................................
14
8.7
Foundation and Concrete Slabs -On -Grade Recommendations................................................
14
8.8
Exterior Concrete Flatwork......................................................................................................
18
8.9
Conventional Retaining Walls..................................................................................................
19
8.10
Lateral Loading.........................................................................................................................
21
8.11
Swimming Pool/Spa.................................................................................................................
21
8.12
Preliminary Pavement Recommendations................................................................................
22
8.13
Site Drainage and Moisture Protection.....................................................................................
24
8.14
Grading and Foundation Plan Review......................................................................................
25
LIMITATIONS AND UNIFORMITY OF CONDITIONS
LIST OF REFERENCES
TABLE OF CONTENTS (Continued)
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geotechnical Map
Figure 3, Slope Stability Analysis
' Figure 4, Wall/Column Footing Detail
Figure 5, Wall Drainage Detail
APPENDIX A
EXPLORATORY EXCAVATIONS
Figures A-1 — A-15, Logs of Borings
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table B-II, Summary of Laboratory Direct Shear Test Results
Table B-III, Summary of Laboratory Expansion Index Test Results
Table B-IV, Summary of Laboratory Water -Soluble Sulfate Test Results
Table B-V, Summary of Laboratory Water -Soluble Chloride Ion Content Test Results
Table B-VI, Summary of Laboratory Atterberg Limits Test Results
Table B-VII, Summary of Laboratory Resistance Value (R-Value) Results
Figure B-1, Gradation Curve
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
1 r�
GEOTECHNICAL UPDATE INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of our geotechnical update investigation and grading plan review for
the proposed mixed density residential development located in La Quinta, California (see Vicinity
Map, Figure 1). The purpose of the investigation is to evaluate subsurface soil and geologic
conditions at the site and, based on the conditions encountered; provide recommendations pertaining
to the geotechnical aspects of developing the property with respect to the project grading plans dated
December 18, 2013.
The scope of our investigation included review of the project grading plans dated December 18,
2013, geologic mapping, subsurface exploration, laboratory testing, engineering analyses, and the
preparation of this report. As a part of our investigation, we have reviewed published geologic maps,
published geologic reports, and previous geotechnical reports related to the property. A summary of
the information reviewed for this study is presented in the List of References.
Our field investigation for PGA West included mapping the fill and alluvium and drilling fifteen
small -diameter borings. Appendix A presents a discussion of the field investigation and logs of the
borings. The approximate locations of the exploratory excavations are presented on the Geotechnical
Map (Figure 2). We performed laboratory tests on soil samples obtained from the exploratory
excavations to evaluate pertinent physical and chemical properties for engineering analysis. The
results of the laboratory testing are presented in Appendix B.
MDS Consulting prepared the grading plans used during our field investigation, and our description
of the proposed site grading is based on those plans. An aerial image of the site was utilized as the
base map for our Geotechnical Map. References to elevations presented in this report are based on the
referenced topographic information. Geocon does not practice in the field of land surveying and is not
responsible for the accuracy of such topographic information.
2. SITE AND PROJECT DESCRIPTION
PGA West, Tract 36537 is the only remaining undeveloped portion of the PGA West community
located in La Quinta, California. The site is generally circular shaped and is bounded by PGA
Boulevard to the west and south, a golf course club house (Stadium Clubhouse) to the east, and a golf
course to the northeast. The northwestern portion of the site extends beyond the circular shape to
meet residential Parcel Map 20426. The site is known as Assessor's Parcel No. 775-220-021 and is
located at latitude 33.6417 and longitude-116.2627. The property is approximately 45 acres which
will be developed to accommodate 130 single-family residences and 30 multi -family residential
buildings with a community clubhouse and pool.
Project No. T2572-22-01 - I - December 20, 2013
The site is located within an alluvial valley which, in its natural condition, sloped gently to the
northeast. Site elevations range from approximately -13 feet above North American Vertical Datum
(NAVD) at the southern portion of the site to approximately 5 feet above seal level on the northern
portion of the site. Elevations on the grading plans reflect the addition of 500 feet to the actual
elevations for ease of use during grading.
Grading of the northeastern portion of the site took place in 1986 (Buena Engineers, 1986) for a
proposed hotel that was not constructed. The site has also been the repository of stock piled fill soils
which were likely locally derived as the surrounding areas were developed. The northern portion of
the site, that joins the residential tract, was previously utilized as the temporary golf course
clubhouse. The temporary structures for the clubhouse were removed and the utilities were
abandoned in -place. The utility equipment boxes, paving and flatwork remain. Subsurface utilities
are present within the site including: a manhole in the central portion; an abandoned well in the west
central portion of the site; and several utilities near PGA Boulevard that were brought into the site as
future tie-ins.
Site development for PGA West will include grading to create 130 single-family residential building
pads, 30 multi -family residential building pads and associated street, utility, and community
recreation improvements. Grading will consist of maximum cuts and fills of approximately 15 and 8
feet, respectively. Maximum fill slope heights are 7.5 feet high or less, at maximum inclinations of
2:1 (horizontal to vertical).
The existing abandoned well in the west central portion of the site should be destroyed in accordance
with the Department of Water Resources Section 13800 of the Water Code or local agencies in
accordance with Section 13801 of the Water Code as part of the site development.
The locations and descriptions provided herein are based on a site reconnaissance, our field exploration,
review of the project grading plans, and project information provided by the client.
3. GEOLOGIC SETTING
The site is located within the Coachella Valley approximately 15 miles northwest of the current Salton
Sea. The Coachella Valley is a pull apart geologic basin formed by extensional faulting and step-overs
along the San Andreas fault. A thickness of more than 3,000 feet of sediment has accumulated within
the Coachella Valley in the last 0.5 million years since the extension began (Brothers, Et. Al, 2009).
The site is located within the area of Ancient Lake Cahuilla in an area currently subject to wind-blown
sand deposits. As such, lacustrine (lake deposits) and eolian (wind-blown) deposits underlie the site.
The sediments consist primarily of fine cohesionless sands with lenses of clays and silts. The deposits
are derived from the Santa Rosa Mountains to the west. The Coachella Valley is considered to be part
Project No. T2572-22-01 - 2 - December 20, 2013
f
of the Colorado Desert geomorphic province which is bounded on the west by the Santa Rosa
Mountains, and the north by the Transverse Ranges. The Colorado Desert extends beyond California to
the east and south. The San Andreas Fault is geologically mapped approximately 12 miles northeast of
the site. Geothermal resources associated with the pull -apart basin are present near the southern area of
the Salton Sea.
Regional subsidence has occurred in recent history within the Coachella Valley. Initial subsidence
occurred between 1920's and 1940's when groundwater was over pumped and ground water levels
declined on the order of 50 feet. Introduction of Colorado River water in 1949 reduced groundwater
pumping and the related subsidence stopped. In the 1970's overdraft of the groundwater once again
began resulting in groundwater level declines of 50 to 100 feet. Subsidence resumed. In 1996 the
United States Geologic Survey (USGS) in cooperation with Coachella Valley Water District (CVWD)
implemented a geodetic measurement of ground levels from Palm Desert, southwestward to the Salton
Sea. Subsidence of 0.39 to 0.57 ft has occurred within the La Quinta Subsidence Zone between 1996
and 2005. Since 2005, CVWD has embarked on a groundwater replenishment program which has
slowed the rate of subsidence in the region. Ongoing studies from the USGS have discovered that the
dominant factor in ground subsidence is the presence of silt layers which compress upon groundwater
withdraw (Sneed, APWA Presentation March 2013). Ground subsidence could occur in the future and
the site could be affected especially if groundwater withdrawal were to re -initiate. We anticipate the
subsidence to be on a regional scale that could cause settlement across the project site. However, the
settlement occurs over a relatively large geographic area and typically does not cause differential
settlement over a relatively short horizontal distance that should be addressed as a design concern as
part of the site development.
4. GEOLOGIC MATERIALS
4.1 General
During our field investigation, we encountered four geologic units consisting of compacted fill (Qcf),
undocumented fill (Qudf), topsoil (unmapped), and older alluvium (Qal). The lateral extent of the
materials encountered is shown on the Geotechnical Map, Figure 2. The descriptions of the soil and
geologic conditions are shown on the boring logs located in Appendix A and described herein in
order of increasing age.
4.2 Compacted Fill (Qcf)
Compacted fill is present within the northeastern portion of the site where the area was graded in
1986 for a proposed hotel site under observation and testing by Buena Engineers (1986). The fill was
encountered within our borings to depths of 10 to 30 feet. It consisted of silty sand to fine sand
which was generally dry to moist and dense to very dense. The compacted fill is considered suitable
Project No. T2572-22-01 - 3 - December 20, 2013
for support of the residential building and site improvements. However, the upper portion of this unit
will require remedial grading.
4.3 Undocumented Fill (Qudf)
Undocumented fill is present within most of the remainder of the site as end -dumped piles, stock
piles, and previously placed undocumented fill. We encountered undocumented fill to depths of 3 to
10 feet. The fill is likely locally derived and was generated from the surrounding development over
the last 28 years. The soils consist of silty sands, fine sands, and silts which are generally dry to
moist and mediums dense to dense. The undocumented fill is not considered suitable for support of
the development and will require remedial grading.
4.4 Older Alluvium (Qal)
Early Holocene to Pleistocene -age alluvium, including the lacustrine and eolian deposits consist of
fine cohesionless sand with lenses of silt and clay, underlie the site. The older alluvium is dry to
moist and medium dense to very dense. Collapse testing indicated the older alluvium beneath the
compacted fill collapsed 0.1 to 0.6 percent upon wetting. The older alluvium in an area with five feet
of undocumented fill (lightly loaded) collapsed 0.8 to 1.6 percent upon wetting. The older alluvium is
considered suitable for support of the residential buildings and site improvements. However, the
upper portion of this unit will require remedial grading.
5. GEOLOGIC STRUCTURE
The geologic structure consists of generally horizontally layered alluvial deposits to depths to several
thousand feet beneath the site overlain by shallow compacted and undocumented fill. The older
alluvium was deposited as part of Ancient Lake Cahuilla during the Tertiary and Pleistocene ages and
likely follows the regional depositional trend and slopes gently to the southeast.
6. GROUNDWATER
We did not encounter groundwater during our exploration to depths of 51.5 feet. Coachella Valley
Water District reports depth to groundwater in an existing well in the vicinity of the site at levels greater
than 96 feet below ground surface (State Well 06S07E16D02S 1999-2013 and 06S07E22B02S 2005-
2013). It is not uncommon for seepage conditions to develop where none previously existed due to the
permeability characteristics of the geologic units encountered. During the rainy season, localized
perched water conditions may develop above silt and clay layers that may require special consideration
during grading operations. Groundwater elevations are dependent on seasonal precipitation, irrigation,
and land use, among other factors, and vary as a result.
Project No. T2572-22-01 - 4 - December 20, 2013
t
7. GEOLOGIC HAZARDS
7.1 Seismic Hazard Analysis
It is our opinion, based on a review of published geologic maps and reports, that the site is not located
on any known active, potentially active, or inactive fault traces. An active fault is defined by the
California Geological Survey (CGS) as a fault showing evidence for activity within the last
11,000 years. The site is not located within a State of California Earthquake Special Study Zone.
According to the computer program EZ-FRISK (Version 7.62), 23 known active faults are located
within a search radius of 50 miles from the property. We used the 2008 USGS fault database that
provides several models and combinations of fault data to evaluate the fault information. Based on
this database, the San Andreas fault, located approximately 8 miles northeast of the site, is the nearest
known active fault and is the dominant source of potential ground motion. Earthquakes that might
occur on the San Andreas or other faults within the southern California and northern Baja California
area are potential generators of significant ground motion at the site. The estimated maximum
earthquake magnitude and peak ground acceleration for the San Andreas fault are 0.80 and 0.56g,
respectively. Table 7.1.1 lists the estimated maximum earthquake magnitude and peak ground
acceleration for the most dominant faults in relation to the site location. We calculated peak ground
acceleration (PGA) using Boore-Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008)
NGA USGS 2008, and Chiou-Youngs (2007) NGA USGS2008 acceleration -attenuation
relationships.
TABLE 7.1.1
DETERMINISTIC SPECTRA SITE PARAMETERS
Fault Name
Distance
from Site
(miles)
Maximum
EarthquakeBoore-
Magnitude (i
Peak Ground Acceleration
Atkinson
2008 (g)
Campbell-
Bozorgnia
2008 (g)
Chiou-
Youngs
2007 (g)
San Andreas
8
8.2
0.34
0.27
0.38
Brawley
14
6.5
0.14
0.13
0.13
San Jacinto
17
7.9
0.23
0.16
0.22
Burnt Mountain
22
6.8
0.15
0.11
0.10
Eureka Peak
23
6.7
0.14
0.10
0.09
Pinto mountain
35
7.3
0.13
0.08
0.09
Emerson
36
7.1
0.12
0.08
0.08
Earthquake Valley
37
6.8
0.10
0.07
0.06
Calico -Hidalgo
37
7.4
0.13
1 0.08
1 0.09
Pisgah -Bullion Mtn -Mesquite
37
7.3
0.12
1 0.08
1 0.09
Project No. T2572-22-01 - 5 - December 20, 2013
In the event of a major earthquake on the referenced faults or other significant faults in the southern
California and northern Baja California area, the site could be subjected to moderate ground shaking.
~ The risk for seismic shaking at the site is considered to be moderate.
We performed a site -specific probabilistic seismic hazard analysis using the computer program
EZ-FRISK. Geologic parameters not addressed in the deterministic analysis are included in this
analysis. The program operates under the assumption that the occurrence rate of earthquakes on each
mapped Quaternary fault is proportional to the faults slip rate. The program accounts for earthquake
magnitude as a function of fault rupture length, and site acceleration estimates are made using the
earthquake magnitude and distance from the site to the rupture zone. The program also accounts for
uncertainty in each of following: (1) earthquake magnitude, (2) rupture length for a given
magnitude, (3) location of the rupture zone, (4) maximum possible magnitude of a given earthquake,
and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected
accelerations from considered earthquake sources, the program calculates the total average annual
expected number of occurrences of site acceleration greater than a specified value. We utilized
acceleration -attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS2008,
Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2007) NGA USGS2008 in the
analysis. Table 7.1.2 presents the site -specific probabilistic seismic hazard parameters including
acceleration -attenuation relationships and the probability of exceedence.
TABLE 7.1.2
PROBABILISTIC SEISMIC HAZARD PARAMETERS
Probability of Exceedence
Peak Ground Acceleration
Boore-Atkinson,
2008 (g)
Campbell-Bozorgnia,
2008 (g)
Chiou-Youngs,
2007 (g)
2% in a 50 Year Period
0.79
0.62
0.78
5% in a 50 Year Period
0.63
0.50
0.63
10% in a 50 Year Period
0.51
0.42
0.51
The California Geologic Survey (CGS) has a program that calculates the ground motion for a
10 percent of probability of exceedence in a 50-year period based on an average of several
attenuation relationships.
While listing peak accelerations is useful for comparison of potential effects of fault activity in a
region, other considerations are important in seismic design, including the frequency and duration of
motion and the soil conditions underlying the site. Seismic design of the structures should be
performed in accordance with the 2010 California Building Code (CBC) guidelines currently adopted
by the City of La Quinta.
Project No. T2572-22-01 - 6 - December 20, 2013
7.2 Liquefaction
Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are
cohesionless/silt or clay with low plasticity, static groundwater is encountered within 50 feet of the
surface, and soil relative densities are less than about 70 percent. If the four previous criteria are met,
a seismic event could result in a rapid pore -water pressure increase from the earthquake -generated
ground accelerations. Seismically induced settlement may occur whether the potential for liquefaction
exists or not. The site is located within a County of Riverside Moderate Liquefaction Potential Zone.
However, groundwater depths are in excess of 96 feet below ground surface. In addition, the existing
fills and older alluvium have soil relative densities in excess of 70 percent. Therefore, the potential
for liquefaction and seismically induced settlement occurring within the site soil is not a design
consideration.
7.3 Expansive Soil
The geologic units will possess a "very low" to "medium" expansion potential (Expansion Index of
90 or less) when placed at the finish grades beneath the proposed structures. The silt and clay lenses
will likely possess the medium expansion potentials on the site, while the sands will likely possess
the very low to low expansion potentials. We expect the proposed grading will expose lenses of silt
and clay during grading. These materials can be selectively graded and placed in the deeper fill areas
at least three feet below finished grade elevations in order to allow for the placement of the low
expansion material at the finish pad grade. Mixing of the silts and clays with the sands during grading
will blend the materials and likely result in a reduced overall expansion potential that the original silts
and clays.
7.4 Landslides
There are no hillsides on or adjacent to the site. The Santa Rosa Mountains are located
approximately I mile south of the site. Therefore, the landslide hazard to the site is not a design
consideration.
7.5 Slope Stability
We understand that the proposed grading at the project site does not include significant cut or fill
slopes as part of the proposed development. In general, it is our opinion that permanent, graded fill
slopes constructed of on -site soils with gradients of 2:1 (horizontal to vertical) or flatter and vertical
heights of 10 feet or less will possess Factors of Safety of 1.5 or greater (Figure 3). Based on the
Rough Grading Plans by MDS Consulting, we understand that planned slopes for the site are inclined
at 2:1 or gentler with total heights of 7.5 feet or less. We should evaluate the stability of planned
slopes that are greater than 10 feet in height if there are changes to the currently planned site grading.
Planned cuts into the existing fill or alluvial materials should be over -excavated and reconstructed
Project No. T2572-22-01 - 7 - December 20, 2013
cr
with compacted fill. Grading of cut and fill slopes should be designed in accordance with the
requirements of the local building codes of the City of La Quinta and the 2010 California Building
Code (CBC).
ft 7.6 Tsunamis and Seiches
A tsunami is a series of long period waves generated in the ocean by a sudden displacement of large
volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or
offshore slope failures. The first order driving force for locally generated tsunamis offshore southern
California is expected to be tectonic deformation from large earthquakes (Legg, et al., 2002). The site
is located 60 miles from the nearest coastline, therefore, the risk associated with tsunamis to be
negligible.
A seiche is a run-up of water within a lake or embayment triggered by fault- or landslide -induced
ground displacement. The site located about 3,000 feet away from manmade Lake Cahuilla, which is
at about Elevation 10 feet. The currently existing Lake Cahuilla is part of the Riverside County Lake
Cahuilla Recreation Area, and does not refer to the Ancient Lake Cahuilla which previously filled the
Coachella and Imperial valleys of southeastern California. The existing lake is a man-made reservoir
that was constructed in the early 1970's and is relatively shallow. Therefore, due to the distance from
the project site, the drainage area between the existing lake and the project site, and the relatively
shallow depth of the water in the lake, the potential of seiches affecting the site or flooding due to a
breach or overtopping of Lake Cahuilla is not a design consideration.
Project No. T2572-22-01 - 8 - December 20, 2013
a
8. CONCLUSIONS AND RECOMMENDATIONS
8.1 General
8.1.1 It is our opinion that soil or geologic conditions were not encountered during the
investigation that would preclude the proposed development of the project provided the
recommendations presented herein are followed and implemented during construction.
8.1.2 Potential geologic hazards at the site include seismic shaking, regional ground subsidence,
and localized expansive soil. Based on our investigation and available geologic
information, active, potentially active, or inactive faults are not present underlying or
trending toward the site.
8.1.3 The undocumented fill is considered unsuitable for the support of compacted fill or
settlement -sensitive improvements based on the potential variability of the unit. Remedial
grading of the surficial soil will be required as discussed herein. The documented fill and
older alluvium are considered suitable to support additional fill and the proposed residential
structures and improvements.
8.1.4 We did not encounter groundwater during our subsurface exploration and we do not expect
it to be a constraint to project development. Seepage and perched groundwater conditions
may be encountered during the grading operations, especially during the rainy seasons.
8.1.5 In general, slopes should possess calculated factors of safety of at least 1.5 when graded at
inclinations of 2:1 (horizontal to vertical), or flatter with maximum heights of 10 feet.
8.1.6 Proper drainage should be maintained in order to preserve the engineering properties of the
fill in the sheet -graded pads and slope areas. Recommendations for site drainage are
provided herein.
8.2 Soil Characteristics
8.2.1 The soil encountered in the field investigation is considered to be "expansive" (Expansion
Index [EI] greater than 20) as defined by 2010 California Building Code (CBC)
Section 1803.5.3. Table 8.2.1 presents soil classifications based on the expansion index.
Project No. T2572-22-01 - 9 - December 20, 2013
r
TABLE 8.2.1
SOIL CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI)
Expansion Classification
2010 CBC Expansion Classification
0 — 20
Very Low
Non -Expansive
21 — 50
Low
Expansive
I
51 — 90
Medium
91 —130
High
Greater Than 130
Very High :�:]
8.2.2 Based on laboratory tests of soil samples, as presented in Appendix B, localized clayey silt
and clay layers within the older alluvium possess a "medium" expansion potential
(Expansion Index of 51 to 90). The existing fill and sand layers within the older alluvium will
likely possess a "very low" to "low" expansion potential (Expansion Index of 50 or less).
Additional testing for expansion potential should be performed once final grades are
achieved.
8.2.3 We performed laboratory tests on samples of the site materials to evaluate the percentage
of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content
tests are presented in Appendix C and indicate that the on -site materials at the locations
tested possess a sulfate content of 0.11 % equating to a S 1 moderate sulfate exposure to
concrete structures as defined by 2010 CBC Section 1904.3 and ACI 318. Table 8.2.2
presents a summary of concrete requirements set forth by 2010 CBC Section 1904.3 and
ACI 318. The presence of water-soluble sulfates is not a visually discernible characteristic;
therefore, other soil samples from the site could yield different concentrations.
Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil
nutrients) may affect the concentration.
TABLE 8.2.3
REQUIREMENTS FOR CONCRETE
EXPOSED TO SULFATE -CONTAINING SOLUTIONS
Water -Soluble
Maximum
Minimum
Sulfate
Exposure
Sulfate
Cement
Water to
Exposure
Class
Percent
Type
Cement Ratio
Compressive
by Weight
by Weight
Strength (psi)
Not Applicable
SO
0.00-0.10
--
--
2,500
Moderate
S1
0.10-0.20
II
0.50
4,000
Severe
S2
0.20-2.00
V
0.45
4,500
Very Severe
S3
> 2.00
V+ Pozzolan
0.45
4,500
or Slag
Project No. T2572-22-01 - 10 - December 20, 2013
}
8.2.4 Laboratory testing indicates the site soils have a pH of 7.9, and possess 0.023% chloride,
and have a minimum resistivity of 750 ohm -cm. The site soils would be classified as
"corrosive" to metal improvements, in accordance with the Caltrans Corrosion Guidelines
(Caltrans, 2012).
8.2.5 Geocon does not practice in the field of corrosion engineering. Therefore, further
evaluation by a corrosion engineer may be performed if improvements that could be
susceptible to corrosion are planned.
8.3 Seismic Design Criteria
8.3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response
Spectra, provided by the USGS to calculate the seismic design parameters. Table 8.3
summarizes design criteria obtained from the 2010 CBC (based on the 2009 International
Building Code [IBC]), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The
short spectral response uses a period of 0.2 second. The structures should be designed using
Site Class D. We will evaluate the structure site class for each residential building once the
final grading has been completed.
Project No. T2572-22-01 - I 1 - December 20, 2013
TABLE 8.3.1
2010 CBC SEISMIC DESIGN PARAMETERS
Parameter
Value
2010 CBC Reference
Site Class
D
Table 1613.5.2
Spectral Response — Class B (short), Ss
1.500g
Table 1613.5 (3)
Spectral Response — Class B (1 sec), S,
0.600g
Table 1613.5 (4)
Site Coefficient, FA
1.000
Figure 1613.5.3 (1)
Site Coefficient, Fv
1.500
Figure 1613.5.3 (2)
Maximum Considered Earthquake
Spectral Response Acceleration (short), SMs
1.500g
Section 1613.5.3 (Eqn 16-36)
Maximum Considered Earthquake
Spectral Response Acceleration — (1 sec), SM,
0.900g
Section 1613.5.3 (Eqn 16-37)
5% Damped Design
Spectral Response Acceleration (short), Sps
1.00Og
Section 1613.5.4 (Eqn 16-38)
5% Damped Design
Spectral Response Acceleration (1 sec), Sp,
0.600g
Section 1613.5.4 (Eqn 16-39)
8.3.2 Based on Section 1803.5.12 of the 2010 CBC, the calculated ground acceleration equal to
Sps/2.5 that should be used for the design of the project is 0.40g.
8.3.3 Conformance to the criteria in Table 8.3 for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur if
a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid
all damage, since such design may be economically prohibitive.
8.4 Grading
8.4.1 Grading should be performed in accordance with the Recommended Grading Specifications
contained in Appendix C and the City of La Quinta Grading Ordinance.
8.4.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the city inspector, owner or developer, grading contractor, civil engineer, and geotechnical
engineer in attendance. Special soil handling and/or the grading plans can be discussed at
that time.
8.4.3 Site preparation should begin with the removal of deleterious material, debris and
vegetation. The depth of removal should be such that material exposed in cut areas or soil
to be used as fill is relatively free of organic matter. Material generated during stripping
and/or site demolition should be exported from the site.
Project No. T2572-22-01 - 12 - December 20, 2013
8.4.4 Undocumented fill and loose alluvium within the limits of grading should be removed to
expose competent fill or dense older alluvium. We anticipate these removals will extend as
much as 10 feet deep. We recommend that the existing materials be over -excavated to a
depth of at least 5 feet below the existing or proposed grades, whichever is deeper, and
replaced as compacted fill. The actual depth of removal should be evaluated by the
engineering geologist during grading operations. We do not expect that removals will need
to extend beyond the limits of grading. The bottom of the excavations should be scarified
to a depth of at least 1 foot, moisture conditioned as necessary, and properly compacted.
8.4.5 We should observe the removal bottoms to check the exposure of the existing fill or older
alluvium. Deeper excavations may be required if dry, loose, or soft materials are present at
the base of the removals.
8.4.6 The fill placed within 5 feet of proposed foundations should possess a "very low" to
"medium" expansion potential (EI of 90 or less), where practical.
8.4.7 If perched groundwater or saturated materials are encountered during remedial grading,
extensive drying and mixing with dryer soil will be required. The excavated materials
should then be moisture conditioned as necessary to near optimum moisture content prior
to placement as compacted fill.
8.4.8 The site should be brought to finish grade elevations with fill compacted in layers. Layers
of fill should be no thicker than will allow for adequate bonding and compaction. Fill,
including backfill and scarified ground surfaces, should be compacted to a dry density of at
least 90 percent of the laboratory maximum dry density near to slightly above optimum
moisture content as determined by ASTM D 1557. Fill materials placed below optimum
moisture content may require additional moisture conditioning prior to placing additional
fill.
8.4.9 Import fill (if necessary) should consist of granular materials with a `low" expansion
potential (EI of 50 or less) generally free of deleterious material and rock fragments larger
than 6 inches if used for capping and should be compacted as recommended herein.
Geocon should be notified of the import soil source and should perform laboratory testing
of import soil prior to its arrival at the site to evaluate its suitability as fill material.
8.4.10 Fill slopes should be overbuilt at least 2 feet and cut back or be compacted by backrolling
with a loaded sheepsfoot roller at vertical intervals not to exceed 4 feet to maintain the
moisture content of the fill. The slopes should be track -walked at the completion of each
slope such that the fill is compacted to a dry density of at least 90 percent of the laboratory
Project No. T2572-22-01 - 13 - December 20, 2013
maximum dry density near to slightly above optimum moisture content to the face of the
finished slope.
8.4.11 Finished slopes should be landscaped with drought -tolerant vegetation having variable root
depths and requiring minimal landscape irrigation. In addition, the slopes should be drained
and properly maintained to reduce erosion.
8.5 Earthwork Grading Factors
8.5.1 Estimates of shrinkage factors are based on empirical judgments comparing the material in
its existing or natural state as encountered in the exploratory excavations to a compacted
state. Variations in natural soil density and in compacted fill density render shrinkage value
estimates very approximate. As an example, the contractor can compact the fill to a dry
density of 90 percent or higher of the laboratory maximum dry density. Thus, the
contractor has an approximately 10 percent range of control over the fill volume. Based on
our experience, the shrinkage of onsite soil is anticipated to be as much as 20 percent.
Please note that this estimate is for preliminary quantity estimates only. Due to the
variations in the actual shrinkage/bulking factors, a balance area should be provided to
accommodate variations.
8.6 Settlement of Proposed Fill
8.6.1 The post -grading settlement (hydrocompression) could reach up to 2 inches. We expect the
settlement will occur over 20 years depending on the influx of rain and irrigation water into
the fill and older alluvium. The settlement will likely be linear from the time the fill is
placed to the end of the settlement period depending on the permeability of the fill soil. We
do not expect the settlement will impact proposed utilities with gradients of 1 percent or
greater. In addition, foundation recommendations are provided herein based on the
maximum and differential fill thickness to account for potential fill settlement.
8.7 Foundation and Concrete Slabs -On -Grade Recommendations
8.7.1 The foundation recommendations presented herein are for proposed residential structures.
We separated the foundation recommendations into two categories based on either the
maximum and differential fill thickness or Expansion Index. We anticipate the majority of
structures will be Category II due to the geometry of the underlying fill and native
materials. However, the category may be increased to Category III where expansive soils
are present within three feet of finish grades in the building pads. The foundation category
criteria for the anticipated conditions are presented in Table 8.7.1. Final foundation
categories will be evaluated once site grading has been completed.
Project No. T2572-22-01 - 14 - December 20, 2013
TABLE 8.7.1
FOUNDATION CATEGORY CRITERIA
Foundation
Maximum Fill
Differential Fill
Category
Thickness, T (Feet)
Thickness, D (Feet)
Expansion Index (EI)
II
T<50
13<20
EI<90
III
T>50
D>20
90<EI<130
8.7.2 We understand that post -tensioned concrete slab and foundation systems will be used for
the support of the proposed structures. The post -tensioned systems should be designed by a
structural engineer experienced in post -tensioned slab design and design criteria of the
Post -Tensioning Institute (PTI), Third Edition, as required by the 2010 California Building
Code (CBC Section 1805.8). Although this procedure was developed for expansive soil
conditions, we understand it can also be used to reduce the potential for foundation distress
due to differential fill settlement. The post -tensioned design should incorporate the
geotechnical parameters presented on Table 8.7.3 for the particular Foundation Category
designated. The parameters presented in Table 8.7.3 are based on the guidelines presented
in the PTI, Third Edition design manual. The foundations for the post -tensioned slabs
should be embedded in accordance with the recommendations of the structural engineer.
TABLE 8.7.2
POST -TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post -Tensioning Institute (PTI)
Third Edition Design Parameters
Foundation Category
II
III
Thornthwaite Index
-20
-20
Equilibrium Suction
3.9
3.9
Edge Lift Moisture Variation Distance, eM (feet)
5.1
4.9
Edge Lift, yM (inches)
1.10
1.58
Center Lift Moisture Variation Distance, eM (feet)
9.0
9.0
Center Lift, yM (inches)
0.47
0.66
8.7.3 Slabs that may receive moisture -sensitive floor coverings or may be used to store moisture -
sensitive materials should be underlain by a vapor retarder. The vapor retarder design should
be consistent with the guidelines presented in the American Concrete Institute's (ACI) Guide
for Concrete Slabs that Receive Moisture -Sensitive Flooring Materials (ACI 302.2R-06). In
addition, the membrane should be installed in accordance with manufacturer's
recommendations and ASTM requirements and installed in a manner that prevents puncture.
The vapor retarder used should be specified by the project architect or developer based on the
Project No. T2572-22-01 - 15 - December 20, 2013
type of floor covering that will be installed and if the structure will possess a humidity -
controlled environment.
8.7.4 The bedding sand thickness should be determined by the project foundation engineer,
architect, and/or developer. However, we should be contacted to provide recommendations
if the bedding sand is thicker than 6 inches. Placement of 3 inches and 4 inches of sand is
common practice in Southern California for 5-inch and 4-inch thick slabs, respectively. The
foundation engineer should provide appropriate concrete mix design criteria and curing
measures that may be utilized to assure proper curing of the slab to reduce the potential for
rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the
foundation engineer present concrete mix design and proper curing methods on the
foundation plans. It is critical that the foundation contractor understands and follows the
recommendations presented on the foundation plans.
8.7.5 The foundations for the post -tensioned slabs should be embedded in accordance with the
recommendations of the structural engineer. A wall/column footing dimension detail is
provided on Figure 4. If a post -tensioned mat foundation system is planned, the slab should
possess a thickened edge with a minimum width of 12 inches and extend below the clean
sand or crushed rock layer.
8.7.6 If the structural engineer proposes a post -tensioned foundation design method other than
the 2010 CBC:
• The criteria presented in Table 8.7.3 are still applicable.
• Interior stiffener beams should be used for Foundation Categories II and 1I1.
• The width of the perimeter foundations should be at least 12 inches.
• The perimeter footing embedment depths should be at least 12 inches, 18 inches
and 24 inches for foundation categories I, II, and III, respectively. The embedment
depths should be measured from the lowest adjacent pad grade.
8.7.7 Our experience indicates post -tensioned slabs are susceptible to excessive edge lift,
regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the
perimeter footings and the interior stiffener beams may mitigate this potential. Because of
the placement of the reinforcing tendons in the top of the slab, the resulting eccentricity
after tensioning reduces the ability of the system to mitigate edge lift. The structural
engineer should design the foundation system to reduce the potential of edge lift occurring
for the proposed structures.
Project No. T2572-22-01 - 16 - December 20, 2013
8.7.8 During the construction of the post -tension foundation system, the concrete should be
placed monolithically. Under no circumstances should cold joints form between the
footings/grade beams and the slab during the construction of the post -tension foundation
system.
8.7.9 Category II, or III foundations may be designed for an allowable soil bearing pressure of
2,500 pounds per square foot (psf) (dead plus live load). This bearing pressure may be
increased by one-third for transient loads due to wind or seismic forces. We estimate the
total settlements under the imposed allowable loads to be about 1 inch with differential
settlements on the order of/2 inch over a horizontal distance of 40 feet.
8.7.10 Isolated footings, if present, should have the minimum embedment depth and width
recommended for conventional foundations for a particular foundation category. The use of
isolated footings, which are located beyond the perimeter of the building and support
structural elements connected to the building, are not recommended for Category III.
Where this condition cannot be avoided, the isolated footings should be connected to the
building foundation system with grade beams.
8.7.11 For Foundation Category III, consideration should be given to using interior stiffening
beams and connecting isolated footings and/or increasing the slab thickness. In addition,
consideration should be given to connecting patio slabs, which exceed 5 feet in width, to
the building foundation to reduce the potential for future separation to occur.
8.7.12 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisture conditioned, as
necessary, to maintain a moist condition as would be expected in such concrete placement.
8.7.13 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
(horizontal to vertical), special foundations and/or design considerations are recommended
due to the tendency for lateral soil movement to occur.
• Building footings should be deepened such that the bottom outside edge of the
footing is at least 7 feet horizontally from the face of the slope.
• Geocon should be contacted to review the pool plans and the specific site
conditions to provide additional recommendations, if necessary.
• Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, the portion of the
swimming pool wall within 7 feet of the slope face be designed assuming that the
adjacent soil provides no lateral support
Project No. T2572-22-01 - 17 - December 20, 2013
• Although other improvements, which are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of
a slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
8.7.14 The recommendations of this report are intended to reduce the potential for cracking of
slabs due to expansive soil (if present), differential settlement of existing soil or soil with
varying thicknesses. However, even with the incorporation of the recommendations
presented herein, foundations, stucco walls, and slabs -on -grade placed on such conditions
may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of
concrete shrinkage cracks is independent of the supporting soil characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper
concrete placement and curing, and by the placement of crack control joints at periodic
intervals, in particular, where re-entrant slab corners occur.
8.7.15 Geocon should be consulted to provide additional design parameters as required by the
structural engineer.
8.8 Exterior Concrete Flatwork
8.8.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations herein assuming the subgrade materials possess an
Expansion Index of 50 or less. Subgrade soils should be compacted to 90 percent relative
compaction. Slab panels should be a minimum of 4 inches thick and when in excess of 8
feet square should be reinforced with 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh or No. 3
reinforcing bars spaced 18 inches center -to -center in both directions to reduce the potential
for cracking. In addition, concrete flatwork should be provided with crack control joints to
reduce and/or control shrinkage cracking. Crack control spacing should be determined by
the project structural engineer based upon the slab thickness and intended usage. Criteria of
the American Concrete Institute (ACI) should be taken into consideration when
establishing crack control spacing. Subgrade soil for exterior slabs not subjected to vehicle
loads should be compacted in accordance with criteria presented in the grading section
prior to concrete placement. Subgrade soil should be properly compacted and the moisture
content of subgrade soil should be verified prior to placing concrete. Base materials will
not be required below concrete improvements.
8.8.2 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade. The
steel reinforcement should overlap continuously in flatwork to reduce the potential for
Project No. T2572-22-01 - 18 - December 20, 2013
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to
the curbs, where possible, to reduce the potential for offsets between the curbs and the
flatwork.
8.8.3 Where exterior flatwork abuts the structure at entrant or exit points, the exterior slab should
be dowelled into the structure's foundation stemwall. This recommendation is intended to
reduce the potential for differential elevations that could result from differential settlement
or minor heave of the flatwork. Dowelling details should be designed by the project
structural engineer.
8.8.4 The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs -on -grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use
of crack control joints and proper concrete placement and curing. Crack control joints
should be spaced at intervals no greater than 12 feet. Literature provided by the Portland
Concrete Association (PCA) and American Concrete Institute (ACI) present
recommendations for proper concrete mix, construction, and curing practices, and should
be incorporated into project construction.
8.9 Conventional Retaining Walls
8.9.1 Retaining walls not restrained at the top and having a level backfill surface should be
designed for an active soil pressure equivalent to the pressure exerted by a fluid density of
40 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than
2:1 (horizontal to vertical), an active soil pressure of 55 pcf is recommended. These soil
pressures assume that the backfill materials within an area bounded by the wall and a 1:1
plane extending upward from the base of the wall possess an EI of 90 or less. For those lots
where backfill materials do not conform to the criteria herein, Geocon should be consulted
for additional recommendations.
8.9.2 Unrestrained walls are those that are allowed to rotate more than 0.001 H (where H equals
the height of the retaining portion of the wall in feet) at the top of the wall. Where walls are
restrained from movement at the top, an additional uniform pressure of 7H psf should be
added to the active soil pressure for walls 8 feet high or less. The portions of the walls that
are planned retaining more than 8 feet should be designed with an additional uniform
pressure of 14H psf.
Project No. T2572-22-01 - 19 - December 20, 2013
8.9.3 The structural engineer should determine the seismic design category for the project. If the
project possesses a seismic design category of D, E, or F, the proposed retaining walls
should be designed with seismic lateral pressure added to the active pressure. The seismic
load exerted on the wall should be a triangular distribution with a pressure of IOH (where
H is the height of the wall, in feet, resulting in pounds per square foot [psfj) exerted at the
top of the wall and zero at the base of the wall. We used a peak site acceleration of 0.40g
calculated from the 2010 California Building Code (SDs/2.5) and applying a pseudo -static
coefficient of 0.33.
8.9.4 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
8.9.5 Retaining walls should be provided with a drainage system adequate to prevent the buildup
of hydrostatic forces and waterproofed as required by the project architect. The soil
immediately adjacent to the backfilled retaining wall should be composed of free draining
material completely wrapped in Miraft 140 (or equivalent) filter fabric for a lateral distance
of 1 foot for the bottom two-thirds of the height of the retaining wall. The upper one-third
should be backfilled with less permeable compacted fill to reduce water infiltration. The
use of drainage openings through the base of the wall (weep holes) is not recommended
where the seepage could be a nuisance or otherwise adversely affect the property adjacent
to the base of the wall. The recommendations herein assume a properly compacted backfill
(EI of 90 or less) with no hydrostatic forces or imposed surcharge load. Figure 5 presents a
typical retaining wall drainage detail. If conditions different than those described are
expected or if specific drainage details are desired, Geocon Incorporated should be
contacted for additional recommendations.
8.9.6 In general, wall foundations having a minimum depth and width of 1 foot may be designed
for an allowable soil bearing pressure of 2,500 psf. The proximity of the foundation to the
top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore,
Geocon should be consulted where such a condition is expected.
8.9.7 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls having a maximum height of 10 feet. In the event that
walls higher than 10 feet or other types of walls are planned, Geocon should be consulted
for additional recommendations.
Project No. T2572-22-01 - 20 - December 20, 2013
8.10 Lateral Loading
8.10.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of
300 pounds per cubic foot (pcf) should be used for the design of footings or shear keys
poured neat against formational materials. The allowable passive pressure assumes a
horizontal surface extending at least 5 feet, or three times the surface generating the passive
pressure, whichever is greater. The upper 12 inches of material in areas not protected by
floor slabs or pavement should not be included in design for passive resistance.
8.10.2 If friction is to be used to resist lateral loads, an allowable coefficient of friction between
soil and concrete of 0.35 should be used for design.
8.11 Swimming Pool/Spa
8.11.1 If swimming pools or spas are planned, the proposed swimming pool shell bottom should
be designed as a free-standing structure and may derive support in newly placed engineered
fill or the competent native older alluvium. It is recommended that uniformity be
maintained beneath the proposed swimming pools where possible. However, swimming
pool foundations may derive support in both engineered fill and undisturbed native
sandstone. It is the intent of the Geotechnical Engineer to allow swimming pool foundation
systems to derive support in both the competent undisturbed sandstone and newly placed
engineered fill as necessary.
8.11.2 Swimming pool foundations and walls may be designed in accordance with the
Conventional Foundation Design and Retaining Wall Design sections of this report (See
Sections 8.6 and 8.13). A hydrostatic relief valve should be considered as part of the
swimming pool design unless a gravity drain system can be placed beneath the pool shell.
8.11.3 If a spa is proposed it should be constructed independent of the swimming pool and must
not be cantilevered from the swimming pool shell.
8.11.4 If the proposed pool is in proximity to the proposed structure, consideration should be
given to construction sequence. If the proposed pool is constructed after building
foundation construction, the excavation required for pool construction could remove a
component of lateral support from the foundations and would therefore require shoring.
Once information regarding the pool location and depth becomes available, this
information should be provided to Geocon for review and possible revision of these
recommendations.
Project No. T2572-22-01 - 21 - December 20, 2013
8.12 Preliminary Pavement Recommendations
8.12.1 The final pavement sections for roadways should be based on the R-Value of the subgrade
soils encountered at final subgrade elevation. Streets should be designed in accordance
with the City of La Quinta specifications when final Traffic Indices and R-Value test
results of subgrade soil are completed. Based on the results of our laboratory R-Value
testing and the variability of the on -site soils, we have assumed an R-Value of 40 for the
subgrade soil and 78 for aggregate base materials for the purposes of this preliminary
analysis. Preliminary flexible pavement sections are presented in Table 8.12.1.
TABLE 8.12.1
PRELIMINARY FLEXIBLE PAVEMENT SECTIONS
Location
Assumed
Traffic
Index
Assumed
Subgrade
R-Value
Asphalt
Concrete
(inches)
Crushed
Aggregate
Base (inches)
Roadways servicing light -duty vehicles
5.5
50
3.0
5.0
Roadways servicing heavy truck vehicles
7.0
50
4.0
7.0
Collector
8.0
50
5.0
8.0
8.12.2 The upper 12 inches of the subgrade soil should be compacted to a dry density of at least
95 percent of the laboratory maximum dry density near to slightly above optimum moisture
content beneath pavement sections.
8.12.3 The crushed aggregated base and asphalt concrete materials should conform to Section
200-2.2 and Section 203-6, respectively, of the Standard Specifications for Public Works
Construction (Greenbook) and the latest edition of the City of La Quinta Specifications.
Base materials should be compacted to a dry density of at least 95 percent of the laboratory
maximum dry density near to slightly above optimum moisture content. Asphalt concrete
should be compacted to a density of 95 percent of the laboratory Hveem density in
accordance with ASTM D 1561.
8.12.4 A rigid Portland cement concrete (PCC) pavement section should be placed in driveway
aprons and cross gutters. We calculated the rigid pavement section in general conformance
with the procedure recommended by the American Concrete Institute report ACI 330R-08
Guide for Design and Construction of Concrete Parking Lots using the parameters
presented in Table 8.14.2.
Project No. T2572-22-01 - 22 - December 20, 2013
TABLE 8.12.4
RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter
Design Value
Modulus of subgrade reaction, k
150 pci
Modulus of rupture for concrete, MR
500 psi
Traffic Category, TC
C and D
Average daily truck traffic, ADTT
100 and 700
8.12.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 8.14.3.
TABLE 8.12.5
RIGID PAVEMENT RECOMMENDATIONS
Location
Portland Cement Concrete (inches)
Roadways (TC=C)
6.5
Bus Stops (TC=D)
7.5
8.12.6 The PCC pavement should be placed over subgrade soil that is compacted to a dry density
of at least 95 percent of the laboratory maximum dry density near to slightly above
optimum moisture content. This pavement section is based on a minimum concrete
compressive strength of approximately 3,000 psi (pounds per square inch). Base material
will not be required beneath concrete improvements.
8.12.7 A thickened edge or integral curb should be constructed on the outside of concrete slabs
subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness or a
minimum thickness of 2 inches, whichever results in a thicker edge, and taper back to the
recommended slab thickness 4 feet behind the face of the slab (e.g., a 9-inch-thick slab
would have an II -inch -thick edge). Reinforcing steel will not be necessary within the
concrete for geotechnical purposes with the possible exception of dowels at construction
joints as discussed herein.
8.12.8 To control the location and spread of concrete shrinkage cracks, crack -control joints
(weakened plane joints) should be included in the design of the concrete pavement slab.
Crack -control joints should not exceed 30 times the slab thickness with a maximum
spacing of 15 feet for the 7-inch-thick slabs (e.g., a 9-inch-thick slab would have a 15-foot
spacing pattern), and should be sealed with an appropriate sealant to prevent the migration
Project No. T2572-22-01 - 23 - December 20, 2013
of water through the control joint to the subgrade materials. The depth of the crack -control
joints should be determined by the referenced ACI report.
8.12.9 To provide load transfer between adjacent pavement slab sections, a butt -type construction
joint should be constructed. The butt -type joint should be thickened by at least 20 percent
at the edge and taper back at least 4 feet from the face of the slab. As an alternative to the
butt -type construction joint, dowelling can be used between construction joints for
pavements of 7 inches or thicker. As discussed in the referenced ACI guide, dowels should
consist of smooth, 1-inch-diameter reinforcing steel 14 inches long embedded a minimum
of 6 inches into the slab on either side of the construction joint. Dowels should be located
at the midpoint of the slab, spaced at 12 inches on center and lubricated to allow joint
movement while still transferring loads. In addition, tie bars should be installed at the as
recommended in Section 3.8.3 of the referenced ACI guide. The structural engineer should
provide other alternative recommendations for load transfer.
8.12.10 The performance of pavement is highly dependent on providing positive surface drainage
away from the edge of the pavement. Ponding of water on or adjacent to the pavement
surfaces will likely result in pavement distress and subgrade failure. Drainage from
landscaped areas should be directed to controlled drainage structures. Landscape areas
adjacent to the edge of asphalt pavements are not recommended due to the potential for
surface or irrigation water to infiltrate the underlying permeable aggregate base and cause
distress. Where such a condition cannot be avoided, consideration should be given to
incorporating measures that will significantly reduce the potential for subsurface water
migration into the aggregate base. If planter islands are planned, the perimeter curb should
extend at least 6 inches below the level of the base materials.
8.13 Site Drainage and Moisture Protection
8.13.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2010 CBC 1804.3 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be
directed into conduits that carry runoff away from the proposed structure.
8.13.2 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of
time.
Project No. T2572-22-01 - 24 - December 20, 2013
8.13.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. We
recommend that area drains to collect excess irrigation water and transmit it to drainage
structures or impervious above -grade planter boxes be used. In addition, where landscaping
is planned adjacent to the pavement, we recommend construction of a cutoff wall along the
edge of the pavement that extends at least 6 inches below the bottom of the base material.
8.13.4 We understand the property may incorporate storm water management devices that
promote water storage but not water infiltration. The existing and planned soil conditions
are not conducive to water infiltration and infiltration should not be performed. In addition,
if water is allowed to infiltrate the soil, seepage may occur through the planned retaining
walls and could cause slope instability. Water storage devices can be installed to reduce the
velocity and amount of water entering the storm drain system but liners will be required if
water in contact with soil.
8.13.5 If not properly constructed, there is a potential for distress to improvements and properties
located hydrologically down gradient or adjacent to these devices. Factors such as the
amount of water to be detained, its residence time, and soil permeability have an important
effect on seepage transmission and the potential adverse impacts that may occur if the
storm water management features are not properly designed and constructed. Based on our
experience with similar clayey soil conditions, infiltration areas are considered infeasible
due to the poor percolation and lateral migration characteristics. We have not performed a
hydrogeology study at the site. Down -gradient and adjacent structures may be subjected to
seeps, movement of foundations and slabs, or other impacts as a result of water infiltration.
8.14 Foundation Plan Review
8.14.1 Geocon should review the structural foundation plans for the project prior to final
submittal. Additional analyses may be required after review of the foundation plans.
Project No. T2572-22-01 - 25 - December 20, 2013
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during construction,
or if the proposed construction will differ from that anticipated herein, Geocon Incorporated
should be notified so that supplemental recommendations can be given. The evaluation or
identification of the potential presence of hazardous materials was not part of the scope of
services provided by Geocon Incorporated.
2. This report is issued with the understanding that it is the responsibility of the owner, or of his
representative, to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into the
plans, and the necessary steps are taken to see that the contractor and subcontractors carry out
such recommendations in the field.
3. The findings of this report are valid as of the present date. However, changes in the
conditions of a property can occur with the passage of time, whether they are due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly
or partially by changes outside our control. Therefore, this report is subject to review and
should not be relied upon after a period of three years.
4. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for geotechnical
aspects of site development are incorporated during site grading, construction of
improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.
Project No. T2572-22-01 December 20, 2013
LIST OF REFERENCES
Boore, D. M. and G. M Atkinson, Ground -Motion Prediction for the Average Horizontal
Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01 and 10.0
S, Eartquake Spectra, Volume 24, Issue 1, pages 99-138, February 2008.
2. Buena Engineers, Inc., Interim Report of Grading Observation and Testing of Hotel Site,
PGA West Hotel Complex, La Quinta, CA, dated November 10, 1986.
3. California Geological Survey (CGS), Earthquake Shaking Potential for California, from
USGS/CGS Seismic Hazards Model, CSSC No. 03-02, 2003.
4. California Geological Survey (CGS), Probabilistic Seismic Hazards Mapping -Ground
Motion Page, 2003, CGS Website: www.conserv.ca.pov/cgs/rghm/pshamap.
5. California Geological Survey, Seismic Shaking Hazards in California, Based on the
USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April
2003). 10% probability of being exceeded in 50 years;
http://redirect.conservation.ca.gov/c sg_/rghm/pshama�/pshamain.html
6. California Geologic Survey, Tsunami Inundation Map For Emergency Planning, State of
California- County of San Diego, La Jolla Quadrangle, dated June 1, 2009.
7. California Department of Transportation (Caltrans), Division of Engineering Services,
Materials Engineering and Testing Services, Corrosion Guidelines, Version 2.0, dated
November, 2012.
8. Campbell, K. W. and Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean
Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response
Spectra for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication
in the NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171,
February 2008.
9. Chiou, Brian S. J. and Robert R. Youngs, A NGA Model for the Average Horizontal
Component of Peak Ground Motion and Response Spectra, preprint for article to be
published in NGA Special Edition for Earthquake Spectra, Spring 2008.
10. City of La Quinta, 2010, Technical Memorandum with Respect to Collapsible Soils for
Geotechnical Reports, Engineering Bulletin 09-03, June 28.
11. Jennings, Charles W. and Bryant, William A., 2010, Fault Activity Map of California,
California Division of Mines and Geology Map No. 6.
12. Legg, M. R., J. C. Borrero, and C. E. Synolakis, Evaluation of Tsunami Risk to Southern
California Coastal Cities, 2002 NEHRP Professional Fellowship Report, dated January.
13. MDS Consulting, 2013, Rough Grading Plan, Tract No. 36537, The Signature, dated
December 18.
14. Risk Engineering, EZ-FRISK, (Version 7.62) 2012.
Project No. T2572-22-01 December 20, 2013
LIST OF REFERENCES (Continued)
15. Sladden Engineering, Supplemental Subsurface Investigation & Remedial Grading
Recommendations, The Signature @ PGA West, Tentative Tract Map No. 36537, La Quinta,
California, dated September 30, 2013.
16. Sladden Engineering, Supplemental Geotechnical Investigation, Proposed Residential
Development, Eden Rock at PGA West, Tentative Tract Map No. 33226, La Quinta,
California, dated April 19, 2011.
17. Sneed, Michelle, 2013, Land Subsidence Presentation to American Public Works
Association, Coachella Valley Branch, March.
18. Treiman, Jerome A., The Rose Canyon Fault Zone Southern California, California Division
of Mines and Geology Publication, 1993.
19. U.S. Geological Survey (USGS), Deaggregation of Seismic Hazard for PGA and 2 Periods of
Spectral Acceleration, 2002, USGS Website: www.earthquake.usgs.gov/research/hazmaps.
20. USGS, 2005, Detection and Measurement of Land Subsidence Using Global Positioning
System Surveying and Interferometric Synthetic Aperture Radar, Coachella Valley, California,
1996-2005, Scientific Investigations Report 2007-5251 Version 2.0, June 2013.
21. USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra,
http://earthquake.usgs.l?ov/research/hazmaps/design/.
Project No. T2572-22-01 December 20, 2013
NO SCALE
COCON �.
W E S T, I N C.
ENVIRONMENTAL GEOTECHNICAL MATERIALS
40-004 COOK STREET - SUITE 4 - PALM DESERT, CA 92211
PHONE (760) 569-9926 - FAX (951) 304-2392
NJT
IMAGE SOURCE: GOOGLE EARTH 2O13
VICINITY MAP
PGA WEST
TRACT 36537
LA QUINTA, CALIFORNIA
ECEMBER, 2013 PROJECT NO. T2572-22-01 FIG. 1
9
LEGEND
OGB15 APPROXIMATE LOCATION OF GEOCON BORING
Qudf UNDOCUMENTED FILL
Qcf COMPACTED FILL
Qal OLDER ALLUVIUM
GEOLOGIC CONTACT
¢^w SITE EPOUNDARY x
Qudf
GB-12 y,
G B-�'..
GB 4 GB-3
Qcf
Qcf
Qudf -. 'GB-8 GB-1 GB 2
------- GB-5
TA_DIUM CLUBHOUSE
OGB-11
T GB 14 �`QB-7 - �>
Qudf `. y► _
k Qudf
T GB-10 /
GA BOULEVAR v`"'
APPROXIMATE SCALE
0 250' 500'
IMAGE SOURCE. GOGGLE EARTH 2O13
ASSUMED CONDITIONS:
SLOPE HEIGHT H = 10 feet
SLOPE INCLINATION 2.0 : 1.0 (Horizontal : Vertical)
TOTAL UNIT WEIGHT OF SOIL yt = 124 pounds per cubic foot
ANGLE OF INTERNAL FRICTION 0 = 28 degrees
APPARENT COHESION C = 200 pounds per square foot
NO SEEPAGE FORCES
ANALYSIS:
xC4 = yH tan 0 EQUATION (3-3), REFERENCE 1
FS = NcfC
EQUATION (3-2), REFERENCE 1
yH
XC4 = 3.3
CALCULATED USING EQ. (3-3)
Ncf = 16
DETERMINED USING FIGURE 10, REFERENCE 2
FS = 2.6
FACTOR OF SAFETY CALCULATED USING EQ. (3-2)
REFERENCES
1...... Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics
Series No. 46,1954
2...... Janbu, N., Discussion of J.M. Bell Dimensionless Parameters for Homogeneous Earth Sipes,
Joumal of Soil Mechanicx and Foundation Design, No. SM6, November 1967
GEOCON
W E IS T. I N C. OR)
ENVIRONMENTAL GEOTECHNICAL MATERIALS
40-004 COOK STREET - SUITE 3 - PALM DESERT, CA 9221 1
PHONE (760) 579-9926 FAX 1951) 304-2392
CER
SLOPE STABILITY ANALYSIS
PGA WEST
TRACT 36537
LA QUINTA, CALIFORNIA
DECEMBER, 2013 1 PROJECT NO. T2572-22-01 FIG. 3
WALL FOOTING
CONCRETE SLAB
SAND .'
A 4 .. •O . O .
PAD GRADE
O , . D.
VISQUEEN
O '
0 0ui
a
FOOTING'*
WIDTH
COLUMN FOOTING
CONCRETE SLAB
•O.'..0..:°.'.'.O.'.o•'..0.'•0..�.b'"'.'.0....0..•..'.b..°.'.'.O.'O...O.':°..'.O.-.o.'.'.4.
°
o .0.' o •p.' .'o -4.' .'o •4.' .'o
•� .'o •O.' .O.'
..'o .4.' o .O.' , .'o -p.' , .'o
o.'0. D. D.
D.
D. o. D....:.
.o.O .o'.'O'¢
SAND ° �. :°•'.'.b. '
.o.�
O '..0. 6.
.o.A .d.'� .. _... .'
VISQUEEN
o o .'�. D.
LL �..0 O..o.'O.
o•'O..o'0..�-4
D. o ?
. , .
1.
FOOTING WIDTH
..... SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION
GEOCON <0�)
W E S T, I N C.
ENVIRONMENTAL GEOTECHNICAL MATERIALS
40-004 COOK STREET - SUITE 4 - PALM DESERT, CA 92211
PHONE (760) 569-9926 FAX (951) 304-2392
CER
NO SCALE
WALL / COLUMN FOOTING DETAIL
PGA WEST
TRACT 36537
LA QUINTA, CALIFORNIA
DECEMBER, 2013 1 PROJECT NO. T2572-22-01 I FIG. 4
GROUND SURFACE
2.0
1�
CONCRETE
BROWDITCH;:
8„
RETAINING WALL
DRAINAGE PANEL
3/4" CRUSHED ROCK
PROPOSED FILTER FABRIC ENVELOPE
GRADE
`` '! ! FOOTING 4" DIA. PERFORATED ABS
OR ADS PIPE
NOTES:
1..-WALL DRAINAGE PANELS SHOULD CONSISTS OF MIRADRAIN 6000 OR EQUIVALENT
2...... FILTER FABRIC SHOULD CONSIST OF MIRAFI 140N OR APPROVED EQUIVALENT
3...... VOLUME OF CRUSHED ROCK SHOULD BE AT LEAST 1 CUBIC FOOT PER FOOT OF PIPE
4...... CONCRETE BROWDITCH RECOMMENDED FOR SLOPE HEIGHTS GREATER THAN 6 FEET
GEOCON
W E S T, I N C. <0D
ENVIRONMENTAL GEOTECHNICAL MATERIALS
40-004 COOK STREET - SUITE 4 - PALM DESERT, CA 92211
PHONE (760) 569-9926 FAX (951) 304-2392
CER
NO SCALE
WALL DRAINAGE DETAL
PGA WEST
TRACT 36537
LA QUINTA, CALIFORNIA
DECEMBER. 2013 1 PROJECT NO. T2572-22-01 FIG. 5
APPENDIX A
EXPLORATORY EXCAVATIONS
_ Our subsurface exploration consisted of drilling 15 small -diameter borings. We performed the field
investigation on October 12 and October 16, 2013. The borings were excavated to a maximum depth
of 51.5 feet with a CME track -mounted limited access or CME 55 truck -mounted rubber tire drill rig
equipped with 8-inch diameter hollow stem augers. The approximate boring locations are shown on
the Geotechnical Map (Figure 2).
We obtained samples during our subsurface exploration in the borings using a California sampler.
The sampler is composed of steel and is driven to obtain ring samples. The California sampler has an
inside diameter of 2.5 inches and an outside diameter of 3 inches. Up to 18 rings are placed inside the
sampler. The rings have an inside diameter of 2.375 inches and are 1 inch in height. We placed the
ring samples in moisture -tight containers and transported them to the laboratory for testing. The
number of blows (blow counts) required to drive the samplers the last 12 inches of the 18 sample
drive (or portion thereof) are reported on the boring logs. The penetration resistance values shown on
the boring logs are shown in terms of blows per foot. These values are not to be taken as N-values
and adjustments have not been applied. We also obtained bulk samples for laboratory testing.
We estimated elevations shown on the boring logs based on available topographic information from
Google Earth. We visually examined, classified, and logged the soil conditions encountered in the
borings and trenches in general conformance with the ASTM International (ASTM) Practice for
Description and Identification of Soils (Visual - Manual Procedure D2844). The logs of the
exploratory borings and trenches are presented on Figures A-1 through A-15 and included herein.
The logs depict the various soil and rock types encountered and indicate the depths at which samples
were obtained.
Project No. T2572-22-01 December 20, 2013
PROJECT
NO. T2572-22-01
W
BORING GBA
o W
DEPTH
SAMPLE
}
O
SOIL
_
~ Q U_
U) ti
We
X Z
IN
FEET
No.
o
Z
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/12/13
F- U) 55 p
o a
T F--
J
O=
(USCS)
W W m
m `
v
n O
C9
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
a
v
0
MATERIAL DESCRIPTION
BI@0'-5'
ML
COMPACTED FILL (Ocfl
SILT, firm, dry -moist, olive -brown
2----
=
--
SP
- - - - - - - - - - - - - - - - - -
SAND, very dense, dry, olive; cohesionless
B 1 @2.5'
50/5"
102.1
2.6
4
B1@5'
50/6"
101.6
3.1
6
-Slight moisture increase; trace silt
g
Bl@7.5'
- - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - ---_---
5DL4'_
1LZ2
_63_
_ML
SP
_SIL_T,stiff,m_oist,olive ____ ________________
SAND, very dense, moist, olive; slightly indurated; laminated
10
Bl@10'
SM
Silty SAND, very dense, moist, olive; sand is fine grained; laminated
50/4'
111.2
5.9
12
— — —
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
— — —
— — —
— — —
ML
SILT, hard, moist, olive; laminated; some small shells; dark grey staining
1@12.5'
69
117.0
13.6
I@13'-1
14
BI@15'
-Trace small shells
73/11"
108.0
3.4
16
18
l@17.5'
SP
SAND, very dense, dry, light olive; trace silt; trace iron oxide staining;
82
104.8
2.9
micaceous; cohesionless
20
B 1 @20'
69
102.6
2.5
22
1 @22.5'
72
103.3
2.6
24
B I @25'
57 -
100.8
2.8
26
ML
OLDER ALLUVIUM (Oal)
28B
1@27.5'
SILT, firm, moist, olive, light orange; mottled color; laminated
17
85.4
7.5
Figure A-1, T2572-22-01 BORING LOGS.GPJ
Log of Boring GBA, Page 1 of 2
SAMPLE SYMBOLS ❑ SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
}
IX
W
BORING GBA
Z W
DEPTH
O
Wo
SAMPLE
NO.
00
0
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/12113
�
w O
W U
a
W
j W
FEET
z
0
(uscs>
m
}.
Oz
O
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
a
o
30
MATERIAL DESCRIPTION
B1 @ 30 '
21
99.0
19.9
32
— — —
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — ---
— — —
— — —
— — —
ML,/MH
SILT, stiff, moist, dark grey olive; some small shells
1 @32.5'
31
102.4
6.4
34
---
------I--------------------------
SAND, medium dense, dry, olive; fine grained; cohesionless
Total depth: 34'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-1 , T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-1, Page 2 of 2
SAMPLE SYMBOLS El SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED, IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT
NO. T2572-22-01
W
BORING GB-2
o W
--
DEPTH
}
O
Q
SOIL
F- Z LL
co '�
W
IX F
IN
FEET
SAMPLE
NO
=
Z
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/12113
�QU)
w U) O
Z �'
lu
a
Z
F-
J
=O
(USCS)
Z w m
LU v
v
20
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
o
°
0
0
MATERIAL DESCRIPTION
NIL
COMPACTED FILL (Ocf1
SILT, firm, dry, olive
2
B2@2.5'
�- .'I•
SM
Silty SAND, very dense, dry -moist, olive; sand is very fine grained;
86
107.9
4.6
I II
slightly indurated
{
B2@5'
I
---
---------------------------------
—44_
1222_
_4I�
6
ML
Sandy SILT, hard, moist, olive; sand is fine grained; laminated; indurated
8
B2@7.5'
_
-Becomes very dark grey -olive; trace shells
—7& _
1122.
—Zl—
:•::
Sp
--------------------------------
SAND, very dense, dry, light olive; micaceous; cohesionless
10
B2@10'
-Becomes very dense/hard, dry -moist; some olive silt chunks; mottled
78
107.8
7.9
texture
12
2@ 12.5'
----------------------
NIL
SILT, hard, moist, very dark grey to black; organic stained; slight organic
14
odor; 1/4" section of 1/8" diameter twig in sample
B2@ 15'
75
117.3
9.9
16
-Becomes dry -moist; some fine sand; some small shells
18
2@17.5'
83/10"
108.9
5.1
Becomes dark olive, moist; laminated
20
— — —
SP
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
SAND, dense, moist, light olive; medium grained; cohesionless
-----
— — —
— — —
B2@20
54
103.9
3.0
22
2@22.5'
72
103.1
4.9
-Becomes very dense, dark olive; fine grained
24
B2@25'
41
97.1
4.4
26
OLDER ALLUVIUM (Oal1
28
2@27.5'
-
SAND, medium dense, moist, olive, light orange; mottled coloring; fine
33
94.6
10.0
_ ML
— grained; iron oxide staining; laminated— — — — — — — — — — — — — — — Jr
— — —
— — —
— — —
�- -�-
SP
�— SILT, stiff, moist, olive
---------------------/
Figure A-2, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-2, Page 1 of 2
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-2
o W ^
DEPTH
SAMPLE
}
O
Q
SOIL
F Z�
V) ^
LL
\
I F
IN FEET
No.
o
Z
cL,nss
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/12/13
U) o
�a
m LLI
J
= O
(uSCs)
UJ w m
v
v
20
c�
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
o-
o
v
30
MATERIAL DESCRIPTION
B2@30'
J. "'I•
SAND, medium dense, moist, olive, light orange; mottled coloring; fine
22
93.2
16.1
grained; iron oxide staining; laminated
32
I• I
SM
_ _SILT, stiff, very moist, olive, yellow, green; mottled color and texture _ _
I- I
Silty SAND, medium dense, moist, olive, light orange; mottled coloring;
fine grained; iron oxide staining; laminated
34
.{�I
B2@35'
I.
33
36
38
•{ �.I•
40
B2@40'
I�I
I. i
-Becomes cohesionless
38
42
I
44
I -I .
B2@45'
I
-Becomes, yellowish olive; cohesionless; with a 1/4" thick dark olive
43
94.9
6.5
46
'�
laminated silt layer
48
.I
50
B2@50'
I i I
59
97.4
6.4
I- I
Total depth: 51.5'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-2, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-2, Page 2 of 2
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
IM ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-3
o W -
DEPTH
}
0
OJ
SOIL
Z
�
I H
IN
FEET
SAMPLE
No.
Oz
Z
cLAss
ELEV. (MSL.) - (-8 ft.) DATE COMPLETED 10/12/13
Q
w Ln O
Z LL:
0 a
Z
N F_
�
(USCs)
z m
>-
O
J
Of
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
a
�
U
MATERIAL DESCRIPTION
0
NIL
COMPACTED FILL (Ocfl
SILT, firm, dry -moist, olive brown
2
---
SP
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
SAND, very dense, moist, dark olive; medium grained; locally massive;
— — —
— — —
---
cohesionless
B3@2.5'
54
107.5
5.6
4
ML
SILT, stiff, wet, dark olive; some small shells; chunk of as halt concrete
B3@5'
in sampler
27
108.9
15.8
6
g
B3@7.5'
— — —
— — — -- — — — — — — — — — — — — — --__
7b._
1L26_
J14-
SP/MI,
Interlayered SAND and SILT, very dense/hard, very moist, dark olive;
sand is fine grained; mottled texture
10
B3 10'
@
— — —
ML
-------ry— — — — — — — — — — — — — — — — — — — — — — — —
SILT, hard, very moist, dark olive; micaceous; some small shells
— — —
68
— — —
108.5
— — —
8.4
12
— — —
SP
------------------g-------------
SAND, verydense, moist, dark olive; fine rained; chunks of silt;
— — —
— — —
— — —
3@12.5'
cohesionless; micaceous
62
111.8
14.1
14
B3@15'
70
112.6
12.8
16
18
3@17.5'
50/6"
101.4
7.2
-Becomes fine to medium grained; trace silt
20
B3@20'
-Becomes very moist to wet
60
108.9
14.6
I
__ __
__ NIL
__ __
SILT, hard, very moist, dark olive
__ __ __ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_ —_
—_ —_ —_
—_ —_ —_
—_ —_ —_ -_
22
_I]
—
SM
_—
—
Silty SAND, medium dense, very moist, dark olive; sand is medium
_-
-_
3@22.5'
grained
45
107.1
I5.0
24
---
ML
---------------------------------
SILT, hard, moist, dark olive; laminated; some small shells
---
---
---
B3@25'
— — —
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
—7D _
108�
_4J_
28
SP
SAND, very dense, moist, olive brown; medium grained; cohesionless;
some silt chunks
28
3@27.5'
53
98.7
6.0
-Trace light iron oxide staining
Figure A-3, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-3, Page 1 of 2
SAMPLE SYMBOLS ❑ ... SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
LLIW
BORING GB-3
Z W
DEPTH
SAMPLE
}
O
SOIL
Q
_
Z U.
W
of
Z
IN FEET
NO
=
Z
class
ELEV. (MSL.) — (-8 ft.) DATE COMPLETED 10/12/13
w U) O
J
uj
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
0.
°
MATERIAL DESCRIPTION
30
B3@30'
-Becomes olive; sand is fine grained
63
96.5
6.9
32
3@32.5'
45
99.6
5.0
34
B3@35'
47
97.7
6.7
36
ML
OLDER ALLUVIUM (Oal
38
3@37.5'
SILT, stiff, moist, olive, yellow, orange; laminated; iron oxide staining;
25
95.7
12.7
micaceous
40
SP
SAND, medium dense, very moist, olive; fine grained; iron oxide
B3@40'
=
= • =
_ --
staining; some small shells
—19 —
9(a�
�L-
ML
-----'---------------------------J
SILT, firm, very moist, olive, orange; mottled coloring; some small shells
42
---
SP/[vII
----Y---------------------------
e;
Interla ered SILT and SAND, medium dense/stiff, moist, olive, orange;
— — —
— — —
— — —
3@42.5
sand is fine grained; very micaceous; iron oxide staining
36
96.0
13.1
44
Total depth: 44'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-3, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-3, Page 2 of 2
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED, IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
}
W
BORING GB-4
Z
DEPTH
0
SOIL
oW"
Q �
Z
Wo
IN
SAMPLE
NO.
=
z
CLASS
ELEV. (MSL.) — (-7 ft.) DATE COMPLETED 10/12/13
w W O
Li-
o �a
Z
m F-
FEET
I._
=)
O
(USCS)
Lu
0: v
20
m
O
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
0-
o
v
0
MATERIAL DESCRIPTION
B4@0'-5'
SP
COMPACTED FILL (Oct)
SAND, loose to medium dense, dry -moist, olive brown; fine grained
NIL
— — —
SILT, hard, dry, olive
B4@2.5'
65
117.5
9.0
4
---
-------y-----------------------
— — —
— — —
— — —
SP
SAND, dense, moist, olive; fine grained; trace to some silt;
cohesionless
B4@5'
52
100.3
3.6
6
SP/NE
Interlayered SAND and SILT, medium dense/hard, moist, olive; flagging
8
B4@7.5'
tape fragment in sample
45
110.9
15.8
10
B4 10'
@
---
ML
----------------------grained ---------
SILT with sand, stiff, moist, dark olive; sand is fine
---
36
— — —
115.6
— — —
11.1
12
4@ 12.5'
90
120.3
13.3
-Becomes hard, olive, orange; mottled coloring; micaceous; dark grey
14
organic staining
B4@ 15'
62
110.3
14.5
16
-Becomes olive; black organic staining; mottled texture
ML
OLDER ALLUVIUM Wall
18
4 17.5'
�°
:.::. -
—
SILT, stiff, moist, olive, orange laminated; iron oxide staining J
�4 _
92 8_
_43_
SP
— ------------ — — — —
SAND, medium dense, moist, olive; cohesionless
20
B4@20'
59
99.3
3.0
-Becomes dense; trace iron oxide staining
22
4@22.5'
44
104.5
2.7
24
B4@25'
48
103.5
2.5
26
Total depth: 26.5'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-4, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-4, Page 1 of 1
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-5
Z W
--
DEPTH
}
OJ
Q
SOIL
~ Z LL
N
F
IN
FEET
SAMPLE
NO
Z
CLASS
ELEV. (MSL.) — -8 ft.) DATE COMPLETED 10/12113
Q Q
p
Z U_
Oam
=Z
�
(USCS)
WJO v
f v
20
C9
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
n-
o
v
0
MATERIAL DESCRIPTION
NIL
COMPACTED FILL (Ocfl
W
SILT, firm, dry -moist, olive
2
--
---
SP
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
SAND, dense, moist, olive; very fine grained; cohesionless
— — —
— — —
---
B5@2.5'
59
101.1
4.0
4
B5@5'
82/I1"
99.8
4.1
6
— — —
NIL
---Y— — — — — — — — — — — — — — — — — — — — — — — — — — — —
Sand SILT, hard, moist, dark olive; sand is fine grained; some small
— — —
— — —
— — —
g
B5@7.5'
shells
90/111,
116.7
11.3
10
B5@10'
-Becomes stiff; trace small shells
41
112.5
14.9
12
5@ 12.5'
83
123.0
12.7
-Becomes dark grey, olive; mottled coloring; grass blade in sample
14
BS 15'
@
---
— SP
----------------g---------------
SA_N_D,_dense, light oliv_e;_fine_rained; cohesionless
---
1i5 —
---
1184_
---
—128_
16
ML
_ _moist, _ _ _ _ _ _ _
SILT, hard, moist, grey olive; fine grained; some small shell fragments
SP
OLDER ALLUVIUM (Oall
18
B5@17.5'
SAND, dense, moist, light olive brown; fine grained; cohesionless;
66
105.2
2.2
locally massive
20
B5@20'
48
103.0
2.6
22
5@22.5'
-Becomes medium dense
28
102.0
2.5
24
B5@25'
33
101.8
3.0
26
Total depth: 26.5'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-5, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-5, Page 1 of 1
❑ SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
Ix
LLI
BORING GB-6
Z LLI
DEPTH
0
SOIL
0
- z
to _71
IX ~
IN
SAMPLE
NO.
—01
0
0
z
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/12/13
<
� I-_
U)
—
Z LL
=)
F- Z
LU
D F-
FEET
0
(USCS)
LU 0
z Go _j
im
of
0 z
20
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
auj
Lu
MATERIAL DESCRIPTION
B6@0'-5'
SP
COMPACTED FILL (Ocfl
SAND, medium dense, dry -moist, yellowish olive brown; fine grained
2
B6@2.5'
65
99.7
3.4
4
Nu-
- - - - - - - - - - - - - - - - - - - - - - - - - - - -
�11, d, moist, dark olive; some shell fragments
T,
- - - -
- - - --
- - - -
B6@5'
Il
83
116.3
7.9
--
- - - -
SP
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SAND, dense, dry -moist, light olive brown; fine grained; cohesionless
- - - -
- - - - --
---
8
B6@7.5'
87/11
114.5
6.0
- - -
SP/Sm
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Interlayered SAND and silty SAND, dense, moist, dark olive; laminations
- - - -
- - - - --
- - - -
between layers
- 10 -
B6@10'
-
--
- - - -
ML
- - - - T - - - - T - - - - - - - - - - - - - - - - - - - - - - - -
SILT with sand, hard, moist, dark olive grey; sand is fine grained; some
- - - -
50/6"
- - - - --
116.0
- - - -
13.5
-
shell fragments
- 12 -
- -
B6@ 12.5 -
- -
-
- - - -
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
_U -
- 108.3_
-9-4-
_ SP
-,%--SAND, dense, moist, olive; fine grained; cohesionless -
- - - -
- - - - --
- - - -
- 14 -
ML
SILT with sand, hard, moist, dark grey olive; sand is fine grained; trace
-
grass pieces; organic staining
B6@ 15'
46
111.0
15.8
- 16 -
-Trace twig fragments
SP
OLDER ALLUVIUM (Oal
18
B6@ 17.5'
SAND, dense, moist, light olive brown; fine grained; cohesionless
65
104.3
2.3
20
B6@20'
72
106.3
2.2
Total depth: 21.5'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-6, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-6, Page 1 of 1
SAMPLE SYMBOLS El SAMPLING UNSUCCESSFUL 1] STANDARD PENETRATION TEST 0 DRIVE SAMPLE (UNDISTURBED)
0 DISTURBED OR BAG SAMPLE Lj CHUNK SAMPLE Y WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
w
BORING GB-7
>.
LU
SOIL
Z
Ow
h-ZLL
tq^
W
IN
FEET
SAMPLE NO
o
Z
cLAss
ELEV. (MSL.) — (-10 ft.) DATE COMPLETED 10/12/13
LU N
o O
H
=)
O
(USCS)LU
ZWm
�a
�O
0
ELu QUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
a v
°
v
MATERIAL DESCRIPTION
0
SP
COMPACTED FILL (Oct)
SAND, loose to medium dense, dry -moist, light olive brown; fine grained
2
�- • I•
— —
SM
— — — — — — — — — — — — -- —— — — — — — — --
Silty SAND, very dense, moist, olive; sand is fine grained; some chunks
— — —
— — —
---
B7@2.5'
I• I
of silt
88
110.9
5.5
4
B7@5'
i I
-Becomes less silty
50/6"
102.4
5.6
g
B7@7.51
1 i II
-� • 4 r
-Becomes dense, dark olive; interlayered with silt
50/6"
110.8
8.8
10
B7@10'
UL
OLDER ALLUVIUM (Oall
61
106.2
21.3
SILT, hard, moist, olive; laminated; some iron staining; carbonate chunks
12
---
----Y----------------------------
SP/MI
Interla ered SAND and SILT, dense/hard, moist, olive; silt is laminated;
---
---
---
7@12.5'
some iron oxide staining
80/11"
120.7
9.4
14
B7@ 15'
— — —
SP
------------g-------------------
SAND, verydense, moist, light olive brown; cohesionless
— — —
78.
— — —
104.0
— — —
3.8
16
18
7@ 17.5'
49
99.8
3.6
Total depth: 19'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
rigure A-7, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-7, Page 1 of 1
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
rvU i c. i nc LUu Ur 5Utl5UHhAGE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT
NO. T2572-22-01
W
BORING GB-8
Z W
DEPTH
}
O
Q
SOIL
0-Z LL
to
XIN H
FEET
SAMPLE
No.
=
Z
CLASS
ELEV. (MSL.) — (-7 ft.) DATE COMPLETED 10/12/13
Q
w U) O
Z LL
° a
= Z
W
J
=O
(USCS)
W W Co1%
v
20
EQUIPMENT HOLLOW STEM AUGER BY: L. BATTIATO
a .,
°
v
0
MATERIAL DESCRIPTION
SP
COMPACTED FILL Well
SAND, loose, medium dense, dry -moist, light olive brown; fine grained
2
B8@2.5'
50/6"
109.8
5.7
-Becomes very dense; cohesionless
4
ti
•"I •
— — —
SM
--
Ty------------------g----------
Silty SAND, dense, moist, dark olive; sand is fine rained; trace shell
— — —
— — —
— — —
i
fragments; laminated
6
B8 5'
@
i •� �
71
117.6
13.5
g
B8@7.5'"-�
62
117.6
14.3
10
B8@10'
1
.� "
-Becomes dark grey from organic staining; with fine grass pieces
61
114.3
15.7
12
�. I.
8@12.5'
55
115.2
14.4
Becomes dense, olive brown
B8@15'
i '�
24
98.8
23.7
16
ML
OLDER ALLUVIUM (Oah
SILT, hard, moist, light olive grey, orange; trace small shells
18
8@17.5'
— —
— --— — — — — — — -- — — — — — — — — — — — —
-i_
103fi
—2fa_
SP
SAND, dense, moist, light olive brown; fine grained; light iron oxide
staining; cohesionless
20
B8@20'
41
102.7
2.0
Total depth: 21.5'
No groundwater encountered
Backfilled with soil cuttings 10/12/2013
Figure A-O, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-8, Page 1 of 1
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL IU ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT
NO. T2572-22-01
LLI
BORING GB-9
Z LU
DEPTH
SAMPLE
O
OJ
Q
SOIL
0-Z LL
Q to
U) '�
Z LL
W
H
� Z
FEET
NO
o
Z
CLASS
ELEV. (MSL.) — (-10 ft.) DATE COMPLETED 10/16/13
w CO p
Lu
° a
D H
J
O°
(uSCs)
W w m
.,
I v
20
C9
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
n.
°
v
0
MATERIAL DESCRIPTION
9@0'-2.
SP/SM
UNDOCUMENTED FILL (Oudfl
SAND with silt, loose, dry to dry -moist, light olive brown; sand is fine
grained
2
B9 2.5'
@
-'II-
— — —
SM
-- ty---------- g--------g--------
Silty SAND, dense, moist, light brown; sand is fine rained
---
50/6'
---
97.6
---
4.0
I�•
4
_i
•� r
B9@5'
::�
i .:I.
-Becomes light olive brown
84
102.8
4.1
6
g
B9@7.5'
---
NIL
---------------------------------
Sandy SILT, medium dense to dense, dry moist to moist, light brown;
---
44
---
113.9
---
14.3
sand is fine grained
10
B9@10'
50/4"
107.4
2.4
SP
OLDER ALLUVIUM (Gall
12
SAND, dense, dry -moist, light olive brown; fine grained
9@ 12.5'
52
96.2
3.3
14
B9@15'
63
98.0
2.8
16
Total depth: 16.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-9, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-9, Page 1 of 1
SAMPLE SYMBOLS ❑ SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
19 ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-10
o W
a
DEPTH
}
OJ
Q
SOIL
Z u
Q F-
c"
ul LL
X F
=
IN.FEET
SAMPLE
NO.
=
Z
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10116/13
w � O
0 E
Z
Lu
D
J
=FO
O
(USCS)
W W m
v
20
Ix
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
a
O
U
0
MATERIAL DESCRIPTION
B 10@
�• . I.
SM
UNDOCUMENTED FILL (Oudt)
0'-2.5'
II i II
t• t
Silty SAND, loose, dry to dry -moist, light brown; sand is fine grained
2
{ I.
10@2.5'
�. I.
-Becomes dense, moist
59
100.9
16.5
4
B10@5'
— — —
SP/SM
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
SAND with silt, very dense, dry -moist, light brown; sand is fine grained
— — —
92/11"
— — —
99.6
---
2.8
6
g
B 10@7.5'
:': ::
---------__
-51_
1018-
_J335_
ML
Sandy SILT, dense, moist, olive; sand is fine grained
10
B10@10'
SP
OLDER ALLUVIUM (Oal)
70
96.7
3.3
SAND, dense, dry to dry -moist, light brown; some iron oxide staining
12
310@12..5
69
101.3
3.5
14
B10@15'
70
104.4
2.1
16
Total depth: 16.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-10, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-10, Page 1 of 1
SAMPLE SYMBOLS El... SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-1
W
DEPTH
SAMPLE
}
0
�
SOIL
o
Q U)
� Z
co
Z LL
Wa
IX Z
IN
FEET
NO
J
=
z
CLASS
ELEV. (MSL.) — (-8 ft.) DATE COMPLETED 10/16113
w U) p
E
J
70
(USCS)
w m
Of v
2 O
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
a
MATERIAL DESCRIPTION
0
BI1@
ML
UNDOCUMENTED FILL (Oud11
0'-2.5'
Sandy SILT, loose, dry to dry -moist, light olive brown; sand is fine
grained
2
11@2.5'
39
84.8
5.6
4
B11@5'
SP
OLDER ALLUVIUM (Oall
51
97.1
2.7
6
SAND, dense, dry to dry -moist, light brown; fine grained; slight iron
oxide staining
g
11 @7.5'
49
99.0
4.8
10
B11@10'
60
102.6
1.5
-Becomes fine to medium grained
12
11@l2. 5
64
106.6
6.1
14
B11@15'
SP/SM
SAND with silt, medium dense, dry -moist, light brown; sand is fine
36
94.5
4.9
16
grained
18
311@1T
52
91.7
1.8
20
B11@20'
ML
SILT with sand, medium dense, dry -moist, light olive brown; sand is fine
29
91.3
5.4
grained; micaceous
22
11@22.
— — —
-----------� ---g— — — — — — — — ------
-5Q—
---
---
SP/SM
SAND with silt, dense, moist, light brown; sand is fine grained;
24
micaceous
B 1 I @25'
41
97.3
2.9
26
TT
Trace organics; iron oxide staining
28
11@27.
-Slight iron oxide staining, no organics
50
Figure A-11, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-11, Page 1 of 2
SAMPLE SYMBOLS ❑ SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST .... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT
NO. T2572-22-01
}
W
BORING GB-11
Z w
DEPTH
SAMPLE
i
Q
SOIL
O Z�
g Q t`q
W"
Z U_
H
Z
IN
FEET
NO.
z
CLASS
ELEV. (MSL.) — (-8 ft.) DATE COMPLETED 10/16/13
w U) O
° a
Lu
`A
J
O=
(USCS)
W w m
IY v
20
IX
O
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON30
v
MATERIAL DESCRIPTION
BI1@30'
' • ' "'•:
---
---------------------------------
�2—
92L
_3�—
CL
Lean CLAY, hard, dry -moist, olive brown; laminated; some iron oxide
staining
32
---
ML
---------ry --�---g--------------
SILT with sand, very dense, moist, light ht olive brown; sand is fine
---
— — —
---
11@32.
grained; laminated; slight iron oxide staining
80
94.9
6.8
34
B11@ 35'
— — —
SP/SM
— — — — — — — — — --� — — — — — — — — — — — — — — —
SAND with silt, very dense, moist, light
ht brown; sand is finegrained;
— — —
84
— — —
— — —
36
slight iron oxide staining
38
11@37.
83
94.3
3.4
40
B 11 40'
SP
SAND, very dense, moist, light brown; fine to medium grained
69
42
11 @42.
78
44
��—
— — —
SM
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — —
Silty SAND, very dense, dry -moist, olive brown; sand is fine grained
— — —
— — —
---
B11@45'
.l.i
- - -
SP/SM
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
SAND with silt, very -dense, dry -moist, olive brown; sand is fine grained
- - -
68
- - -
97.4
---
2.7
46
48
11@47.
:.•...::
— — — — — — — — — — — — —
—
NE
SILT with sand, very dense, dry -moist to moist, olive brown; sand is fine
grained; laminated; some iron oxide staining
50
B11@50'
56
95.0
7.6
Total depth: 51.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-11, T2572-22-01 BORING LOGS.GPJ
Log of Boring GBA 1, Page 2 of 2
SAMPLE SYMBOLS ❑ SAMPLING UNSUCCESSFUL 11 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-12
o W
o
DEPTH
SAMPLE
}
0O
SOIL
U �-
Q
Z L
W
Ix
IN
NO
2
Z
CLASS
ELEV. (MSL.) — (-6 ft.) DATE COMPLETED 10/16/13
F
w Cl) O
O
E
F- F
rn W
FEET
J
=O
(USCs)
W Z m
o v
20
IX
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
o
MATERIAL DESCRIPTION
0
B12@
�- - I-
SM
COMPACTED FILL We
V-2.5'
i II
Silty SAND, medium dense, dry -moist, light olive brown; sand is fine
grained
2
-{ -I-
l2@2.5'
1'
— — —
— — — — — — — — — --� — — — --------------
5DL6
103Z
_2JL
SP/SM
SAND with silt, very dense, moist, light ht brown,
4
B 12@5'
68
107.3
4.6
6
-Becomes dense
g
B 12@7.5'
-Becomes very dense
50/6"
104.7
9.2
10
B12@10'
�- -'I-
SM
OLDER ALLUVIUM (Oal)
86
110.7
5.0
Silty SAND, very dense, dry -moist to moist; sand is fine grained;
laminated; micaceous
12
12@12.-'j-
57
14
I•�
B12@15'
I
ML
SILT, medium dense, moist, olive brown; laminated
51
104.1
16.9
16
---
SP
-----------�---g-----g---------
SAND, medium dense, moist, li ht brown; fine rained
— — —
— — —
---
18
12@17.
____
-5i_
111E
_i2�
ML
SILT with SAND, medium dense, moist, olive brown; sand is fine
grained; micaceous
20
B 12@20'
— — —
SP
-----------------------------------
SAND, very dense, dry -moist, light brown; fine grained
---
90/11 '
---
---
Total depth: 21.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-12, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-12, Page 1 of 1
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
IM ... DISTURBED OR BAG SAMPLE Ll ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT
NO. T2572-22-01
W
BORING GB-13
o W
R
DEPTH
}
00
Q
SOIL
F Z LL
0
cr
IN
FEET
SAMPLE
NO.
0
2
z
CLASS
ELEV. (MSL.) — (-5 ft.) DATE COMPLETED 10/16113
U)
w O
LL
W
o a
F Z
m
J
07
(USCS)
cnlW W m
m `�
CY
O
m
O
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
a
o
v
0
MATERIAL DESCRIPTION
B 13@
�. . I.
SM
UNDOCUMENTED FILL (Oudt)
0'-2.5'
i
Silty SAND, medium dense, dry to dry -moist, light olive brown; sand is
2
{ .I
fine grained
13@2.5'
1
SP
OLDER ALLUVIUM (Oal)
4
SAND, very dense, dry, light brown; fine grained
B 13@5'
50/5"
116.3
10.4
6
ML
— — — — — — — — — — — — — — —
SILT, very dense, moist, olive brown
— — —
— — —
---
g
13@7.5'
I
90/I1"
107.1
5.2
- I-
---
SM
--
ry---------------------------
Silty SAND, verydense, moist, light ht olive brown; sand is fine grained
ained
— — —
— — —
— — —
10
B13@10'
{ J. I.
61
109.3
15.1
---
ML
---------------------------------
SILT, dense, moist, olive; some organics; some fine shells
---
---
---
12
13@ 12.5
50
14
— — —
-----------�---g-----g---------
---
— — —
— — —
SP
SAND, medium dense, moist, light brown; fine rained
B13@15'
35
99.8
2.3
16
Total depth: 16.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-13, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-13, Page 1 of 1
SAMPLE SYMBOLS ❑ SAMPLING UNSUCCESSFUL ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-14
o W
DEPTH
SAMPLE
}
0O
3
SOIL
Q LL
Z LL
Z
FEET
N0.
J
=
Z
CLASS
ELEV. (MSL.) — (-9 ft.) DATE COMPLETED 10/16113
w N O
0 a
�
J
O
(usCs)
W p Co
o v
20
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
a -
0
MATERIAL DESCRIPTION
B 14@
�- -'I.
SM
UNDOCUMENTED FILL (Oudf)
0'-2.5'
J
I
Silty SAND, medium dense, dry to dry -moist, light brown
14@2.5'
SF
SAND, dense, dry -moist, light wn bro; sand is fine grained; some iron
75
99.9
3.4
—Sm
oxide staining-------------J
i .
Silty SAND, dense, dry -moist, light brown
B 14@5'
— — —
ML
— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — ---
SILT with sand, dense, dry -moist to moist, olive brown; sand is fine
— — —
65
— — —
115.1
---
11.2
6
grained
8
B 14@7.5'
57
112.5
13.6
10
B14@10'
ML
OLDER ALLUVIUM (Oal)
24
104.9
13.3
SILT, medium dense, moist, olive brown; trace fine shells; laminated
12
14@ 12.5
34
102.1
14.2
-Becomes laminated; iron oxide staining
14
— — —
—— — — — — —— — — — — — — — — — — — — — — — — —
— — —
— — —
— — —
SP
SAND, dense, to moist, light brown; fine rained; some iron
g
oxide staining
B14@15'
55
103.0
2.6
16
18
14@17.5
59
20
B 14@20'
45
101.0
2.5
Total depth: 21.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-14, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-14, Page 1 of 1
SAMPLE SYMBOLS El... SAMPLING UNSUCCESSFUL 91 ... STANDARD PENETRATION TEST 0 ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 3E ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
PROJECT NO. T2572-22-01
W
BORING GB-15
Z W
o
DEPTH
SAMPLE
}
OJ
Q
SOIL
~ Z U.
Q �\n
00 ^
ZLLI LL'
W
I F
Z
IN
NO
2
Z
CLASS
ELEV. (MSL.) — (-6 ft.) DATE COMPLETED 10/16113
U p
m R
rn Lu
FEET
J
O=
(usCs)
W U m
o v
20
0:
EQUIPMENT HOLLOW STEM AUGER BY: C. ROBINSON
a
MATERIAL DESCRIPTION
0
ML
UNDOCUMENTED FILL (Oudo
SILT with sand, medium dense, dry to dry -moist, light olive brown
2
15@2.5'
ML
OLDER ALLUVIUM (Oal)
42
SILT, medium dense, dry to dry -moist, light olive brown; trace fine
4
shells; laminated; some iron oxide staining
B 15@5'
32
6
g
B 15@7.5'
_ _
_ —__ _ __ __ —__ _ —__ — — —
41_
99_6—
_L7_
SP
SAND, medium dense, dry, light brown; fine grained; slight iron oxide
staining
10
1315@10'
38
98.3
2.3
Total depth: 11.5'
No groundwater encountered
Backfilled with soil cuttings 10/16/2013
Figure A-15, T2572-22-01 BORING LOGS.GPJ
Log of Boring GB-15, Page 1 of 1
SAMPLE SYMBOLS SAMPLING UNSUCCESSFUL 10 ... STANDARD PENETRATION TEST ... DRIVE SAMPLE (UNDISTURBED)
® ... DISTURBED OR BAG SAMPLE Q ... CHUNK SAMPLE 1 ... WATER TABLE OR SEEPAGE
NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE
INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
GEOCON
. .ii hop ,oil
Saw
WT
Am
ed
N
`''' i
qwk
x ,
s S
«r�
l
"n9}. 4
t} �
ply--,�^ y"mod
w
ji
r
ON
I
s
# i
y
r
APPENDIX B
LABORATORY TESTING
We performed laboratory tests in accordance with current, generally accepted test methods of ASTM
International (ASTM) or other suggested procedures. We analyzed selected soil samples for in -situ dry
density and moisture content, maximum dry density and optimum moisture content, direct shear strength,
expansion potential, hydro -collapse, water-soluble sulfate, R-Value, and gradation. The results of the
laboratory tests are presented on Tables B-I through B-VI and Figure B-1. The in -place dry density and
moisture content of the samples tested are presented on the boring logs in Appendix A.
TABLE B-I
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557
Maximum
Optimum
Sample No.
Description
Dry
Moisture
(Geologic Unit)
Psity
Content
(% dry wt.)
G131@0-5 (Qaf)
Olive -brown Silty SAND
127.5
10.3
GB4@0-5 (Qaf)
Olive -brown Silty SAND
129.8
10.0
GB9@0-2.5 (Qaf)
Light olive -brown SAND with silt
119.1
12.0
GB11@0-2.5 (Qaf)
Light olive -brown SILT
115.5
13.8
TABLE B-II
SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS
ASTM D 3080
Moisture Content
Peak
Geologic Unit
Dry Density
(%)
Peak
(Ultimate]
After
Sample No.
(Soil Type)
(pet)
[Ultimate]
Angle of Shear
Initial
Cohesion (psf)
Resistance
Test
(degrees)
GB3@7.5
Qaf (SP/ML)
119.6
14.4
16.2
450 [50]
33 [32]
G134@0-51'1
Qaf (SM)
116.8
1 9.7
16.6
200 [200]
28 [27]
G139@7.5
Qaf (ML)
113.9
14.3 f
18.3
350 [200]
1 30 [30]
E'l Sample remolded to a dry density of approximately 90 percent of the laboratory maximum dry density near
optimum moisture content.
Project No. T2572-22-01 - B-1 - December 20, 2013
TABLE B-111
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829
Sample No.
(Geologic Unit)
Moisture Content (%)
Dry Density
c
(p fl
Expansion
Index
Expansion
Classification
2010 CBC
Expansion
Classification
Before
After Test
Test
G1315@2.5-5
11.6
27
103.3
89
Medium
Expansive
(Qudfl
TABLE B-IV
SUMMARY OF LABORATORY HYDROCOLLAPSE TEST RESULTS
ASTM D 5333
Sample No.
Geologic Unit
(Soil Type)
Dry Density
(pcf)
Moisture Content
(%)
Loading
Pressure (psf)
Hydro°collapse
( /o)
Initial
After
Test
GB-3@37.5
Qal (ML)
95.7
12.7
29.2
2500
0.1
GB-3@40
Qal (ML)
96.8
27.2
27.2
2500
0.0
G137@10
Qal (ML)
106.2
21.3
24.0
1600
0.2
G137@12
Qal (SP/ML)
120.7
9.4
14.1
1600
0.4
G137@15
Qal (SP)
104.0
3.8
24.1
1600
0.6
G137@17.5
Qal (SP)
99.8
3.6
21.8
1600
0.6
GB 11 @7.5
Qal (SP)
99.0
4.8
21.5
1600
1.5
GB 11 @ 12.5
Qal (SP)
106.6
6.1
18.9
2000
0.8
GB 11 @ 15
Qal (SP/SM)
94.5
4.9
30.4
2000
1.0
GB 11 @20
Qal (ML)
91.3
5.4
31.4
2500
1.6
TABLE B-V
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO.417
Sample No.
(Geologic Unit)
Water -Soluble
Sulfate (%)
Water -Soluble
Sulfate (ppm)
ACI 318 Sulfate
Exposure
GB 11 @0-2.5
0.111
1108
Moderate (S 1)
Project No. T2572-22-01 - B-2 - December 20, 2013
TABLE B-VI
SUMMARY OF LABORATORY RESISTANCE VALUE (R-VALUE) TEST RESULTS
ASTM D 2844
Sample No. (Geologic Unit) R-Value
G1315@0-2.5 56
Project No. T2572-22-01 - B-3 - December 20, 2013
mmtr■�imm�i�inr �iiim�� ii
iom��■iiim���iinm �■ilium■iiim��
iAnm��;am iinnnuiimm■iiimes
IIRIIIIC�IIIINI��IIIIl95'ri\IIIAII�■IIL9:��
19� �z5i■IIIIIII��!!f tii1��IIIR11lI�iiilllll
loom■iimm■�inm�■,im:;y�iimn
loom■iiimn■imm�■i��inn■iiimu■
100°�■0i1°iiiiiiiiiiiiiiiiniiiii °0��
SAMPLE
ID
SAMPLE DESCRIPTION
G62 35-40'
SM -Silt SAND
GEOCON
W E S T, I N C. fR)
ENVIRONMENTAL GEOTECHNICAL MATERIALS
40-004 COOK STREET - SUITE 4 - PALM DESERT, CA 9221
PHONE (760) 579-9926 - FAX (951) 304-2392
CER/CER
GRAIN SIZE DISTRIBUTION
PGA WEST
TRACT 36537
LA QUINTA, CALIFORNIA
DECEMBER, 2013 PROJECT NO. T22572-22-01 FIG B1
+ - x
s '
.a Al411
tSi
i
i`. f
CIO,
tr 4
"WAR
�jr�
Tf � �'yt 'M�• C � � f a �
£
4;,
y5
s
1
P
two
m
v #�
Es �
APPENDIX C
RECOMMENDED GRADING SPECIFICATIONS
FOR
PGA WEST
LA QUINTA, CALIFORNIA
PROJECT NO. T2572-22-01
Project No. t2572-22-01 - C-1 - December 20, 2013
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon Inland Empire, Incorporated. The
recommendations contained in the text of the Geotechnical Report are a part of the
earthwork and grading specifications and shall supersede the provisions contained
hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, adverse weather, result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as -graded topography.
GIE rev. 02/07
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on -site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil -rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12
inches in maximum dimension and containing at least 40 percent by weight of
material smaller than'/4 inch in size.
3.1.2 Soil -rock fills are defined as fills containing no rocks or hard lumps larger than 4
feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than 12
inches in the maximum dimension.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than'/4 inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
GIE rev. 02/07
r
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on -site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil -rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track -walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, gradation and chemical characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1'/2 inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
GIE rev. 02/07
4.2 Any asphalt pavement material removed during clearing operations should be properly
disposed at an approved off -site facility. Concrete fragments that are free of exposed
reinforcing steel may be placed in fills, provided they are placed in accordance with
Section 6.2 or 6.3 of this document.
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Finish Grade
2
al Ground
Remove All
Unsuitable Material77���
As Recommended By
Consultant Slope To Be Such That
Sloughing Or Sliding
Does Not Occur I Varies
Finish Slope Surface
"B„
t
See Note 1 See Note 2
No Scale
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit
complete coverage with the compaction equipment used. The base of the key
should be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial
material and at least 2 feet into dense formational material. Where hard rock is
exposed in the bottom of the key, the depth and configuration of the key may be
modified as approved by the Consultant.
GIE rev. 02/07
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil -rock fill shall be accomplished by sheepsfoot or segmented -steel
wheeled rollers, vibratory rollers, multiple -wheel pneumatic -tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil -rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557-02.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
GIE rev. 02/07
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in -place
` dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557-02. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill slopes be over -built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track -walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over -building of slopes, slope faces may be back -rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track -walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil -rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 10 feet below finish grade or
3 feet below the deepest utility, whichever is deeper. In the event that placement of
oversized rock is planned less than 10 feet below finish grade, 15 feet behind slope
face, or 3 feet below deepest utility, Geocon should be consulted for additional
recommendations.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
GIE rev. 02/07
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open -face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center -to -center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post -construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing. previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
GIE rev. 02/07
Y
V f
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196-93, may be performed in
both the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of "passes" have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In -place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
GIE rev. 02/07
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. OBSERVATION AND TESTING
7.1 The Consultant shall be the Owner's representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil -rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil -rock fill placed and
compacted.
7.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil -rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
7.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
7.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
7.5 The Consultant should observe the placement of subdrains, to verify that the drainage
v
devices have been placed and constructed in substantial conformance with project
specifications.
7.6 Testing procedures shall conform to the following Standards as appropriate:
G[E rev. 02/07
7.6.1 Soil and Soil -Rock Fills:
7.6.1.1 Field Density Test, ASTM D 1556-02, Density of Soil In -Place By the Sand -Cone
Method.
7.6.1.2 Field Density Test, Nuclear Method, ASTM D 2922-01, Density of Soil and
Soil -Aggregate In -Place by Nuclear Methods (Shallow Depth).
7.6.1.3 Laboratory Compaction Test, ASTM D 1557-02, Moisture -Density Relations of
Soils and Soil -Aggregate Mixtures Using 10-Pound Hammer and 18-Inch Drop.
7.6.1.4. Expansion Index Test, ASTM D 4829-03, Expansion Index Test.
7.6.2 Rock Fills
7.6.2.1 Field Plate Bearing Test, ASTM D 1196-93 (Reapproved 1997) Standard Method
for Nonreparative Static Plate Load Tests of Soils and Flexible Pavement
Components, For Use in Evaluation and Design of Airport and Highway
Pavements.
8. PROTECTION OF WORK
8.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
8.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
GIE rev. 02/07
9. CERTIFICATIONS AND FINAL REPORTS
9.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
' Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
" horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as -built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
9.2 The Owner is responsible for furnishing a final as -graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as -graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
GIE rev. 02/07