33597�e5��
La Quinta, California
Prepared for:
RT. Hughes Co., LLC R t
78 -900 Ave. 47, Suite 200
La Quinta, CA 92253
ro 9 ;9] rid Wit. mlrr- rJp.. `y ip 't r soh .; -) ,i..p
. +q.✓�' d�'},iftek'"' �, s�pv �!�1 u'Stpo II. r`�'!i'pJ "� .i
" 4` M�aG2"tw"; W24k
NOR' 5
-4 U=
� v' Nr wa' O Fra`. �nm s� iu
�YX ' ^ fi�1 ` � k; ,. a '; � ' '-r ". ,' r ,.q)�� `, "x •`ke ' ��* � � � �r , (� � `�yzs ; „ y i {f � :
i
f.Yttx`�`+�.uF6sr��Say�rt�
X 4fy l'Iffl l.,,% -@
9kX r s9
yparfr�ji��Sk a fzt p d rxar 1'€ 1-11 �RHRV
F, ad��� hb d %x+r,.�'y,k��'HC�4� *i
�`'�t
X�� �CO�r ,CC;i�s�
�
41
,�a�rra�
��a,,. �y hri1'� �� •*r �h.c`k� $�4 ����d�dLy +�4�7” u G• jr�°�C�,�� �L k � n`f�
H"�` � ' •r ��,� . �� t t"r � � �ti� s"���s�5�"��f,�`'"a^�,7'r`;p ! ,f t�$¢ �aa� Yr�� ,?� n ,.a, �`�� � � f '
fey` h ��r4r Faf ^ s �M aa7nr7 `jy f Y J ors Y f
2R
,� •+"'F� - �'�r '*�&� �n '� l r�i€�''F"�' �+.t� �E'r �?s r�� � �' �,v' �qy , ..� c - }5�^ 1`i't. � a,� .
�`,i4,
�k d:t'k.
�c a� ``3 NS za r a rddY 1i a yes is "tea .
b 71 '1• Y1•'i - .14,
CF£` t�k 5&- c.- �a�""` j r } �- p` --�un �r 1 rY •1 eF.�,.� t'"i �Jyy .. ,G J 9 a�q+c - i
- nrl +dr'a? -'�t�7 srrn�tL'Ff'^" Y3�4bb vii V �}5.�ys'
-
1 �+' t �}P '� k e�].r n m �" n's.§ +5 `t r++rr ✓ 1, j a Y i�qj r " h'r. y d
+t xank �� x �� a },5 "�•� '+��,�'r v5�f "aaR_ �s ��
t,5�k`Ff y�r,,yTc
t 'L" r�•'F'- 9d 01-1, 1, .1 .,E. $ �r sf�,gC,YQ 4S, J'i��,s*`"ftS�.nx` a`,a- task + f .t x •.�' ,
a � '9'r�> �' �a�1
2'<as+ R ?X
kt 4 c�u#re r
it -> rb to a' t,, a"9i•� a�'r �' v .a»x r r' J
2002 Aerial, Photograph Courtesy of USG S
Prepared by:
ANDM Landmark Consultants, Inc. 0"
ARK
77 -948 Wildcat Drive ,
Geo-Engineers • • Geologists Palm Desert, CA 92211
a vBE/MBE /SBE Company (760) 360-0665
May 2005
LANDMARK
a OBEIMBE/SBE Company
May 27, 2005
Mr. Jerry Green
RT. Hughes Co. LLC
78 =900 Avenue 47, Suite 200
La Quinta, CA 92253
Geotechnical Investigation
Proposed Coral Mountain Estates
SWC of Avenue 60 and Madison Street
La Quinta. California
LCI Report No. LP05098
Dear Mr. Green:
780 N. 4th Street
El Centro, CA 92243
(760) 370 -3000
(760) 337 -8900 fax
77 -948 Wildcat Drive
Palm Desert, CA 92211
(760) 360 -0665
(760) 360 -0521 fax
This geotechnical report is provided for design and construction of the proposed Coral Mountain
Estates residential development located near the southwest corner of Avenue 60 and Madison Street
south of La Quinta, California. Our geotechnical investigation was conducted in response to your
request for our services. The enclosed report describes our soil engineering investigation and
presents our professional opinions regarding geotechnical conditions at the site to be considered in
the design and construction of the project.
The findings of this study indicate the site is underlain by interbedded silty sands and sandy silts.
The subsurface soils are medium dense to dense in nature. Groundwater was not encountered in the
borings during the time of field exploration.
Elevated sulfate and Chloride levels were not encountered in the soil samples tested for this study.
However the soil is severely corrosive to metal. We recommend a minimum of 2,500 psi concrete of
Type II Portland Cement with a maximum water /cement ratio of 0.60 (by weight) should be used for
concrete placed in contact with native soils of this project.
We did not encounter soil conditions that would preclude implementation of the proposed project
provided the recommendations contained in this report are implemented in the design and
construction of this project. Our findings, recommendations, and application options are related only
' through reading the full report, and are best evaluated with the active participation of the engineer
of record who developed them.
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
We appreciate the opportunity to provide our findings and professional opinions regarding
geotechnical conditions at the site. If you have any questions or comments regarding our findings,
please call our office at (760) 360 -0665.
Respectfully Submitted,
Landmark Consultants, Inc.
Kelly T. Nordmeyer
i
M. Ch r% dra, PE
.pal E ineer
ion:
Client (4)
0
Z
' No. C 34432 I
EXPIRES 09 -30 -05
hafiqul Alam
Staff Engineer
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
TABLE OF CONTENTS
Page
Section1
............................................................................................................ ..............................1
INTRODUCTION......................................................................................... ..............................1
1.1
Project Description ............................................................................. ..............................1
1.2
Purpose and Scope of Work ............................................................... ..............................1
1.3
Authorization ...................................................................................... ..............................2
Section2
............................................................................................................ ..............................3
METHODS OF INVESTIGATION ...............................:.............................. ..............................3
2.1
Field Exploration ................................................................................ ..............................3
2.2
Laboratory Testing .............................................................................. ..............................4
Section3
............................................................................................................ ..............................5
DISCUSSION................................................................................................ ..............................5
3.1
Site Conditions ................................................................................... ..............................5
3.2
Geologic Setting ................................................................................. ..............................5
3.3
Seismicity and Faulting ...................................................................... ..............................6
3.4
Site Acceleration and CBC Seismic Coefficients ............................... ..............................7
3.5
Subsurface Soil ................................................................................... ..............................8
3.6
Groundwater ...................................................................................... ...............................
8
3.7 Hydroconsolidation .............................................................................. ..............................8
3.8
Soil Infiltration Rate ........................................................................... ..............................9
Section4
........................................................................................................... .............................10
RECOMMENDATIONS.............................................................................. .............................10
4.1
Site Preparation .................................................................................. .............................10
4.2
Foundations and Settlements ............................................................. .............................12
4.3
Slabs -On -Grade ................................................................................. .............................13
4.4
Concrete Mixes and Corrosivity ........................................................ .............................14
4.5
Excavations ........................................................................................ .............................15
4.6
Lateral Earth Pressures ...................................................................... .............................15
4.7
Seismic Design .................................................................................. .............................16
4.8
Pavements .......................................................................................... .............................16
Section5
........................................................................................................... .............................18
LIMITATIONS AND ADDITIONAL SERVICES ...................................... .............................18
5.1
Limitations ......................................................................................... .............................18
5.2
Additional Services .................:.......................................................... .............................19
APPENDIX A: Vicinity and Site Maps
APPENDIX B: Subsurface Soil Logs and Soil Key
APPENDIX C: Laboratory Test Results
APPENDIX D: Summary of Infiltration Testing
APPENDIX E: References
Proposed Coral Mountain Estates — La Quinta. CA LCI Report No. LP05098
Section 1
INTRODUCTION
1.1 Project Description
This report presents the findings of our geotechnical investigation for the proposed Coral Mountain
Estates residential development located on southwest corner of Avenue 60 and Madison Street south
of La Quinta, California (See Vicinity Map, Plate A -1). The proposed development will consist of
several one to two story single family residential homes on approximately 23- acres. A site plan for
the proposed development was provided by RT. Hughes Co., LLC of La Quinta, California.
The structures are planned to consist of continuous footing with slabs -on -grade and wood -frame
construction. Footing loads at exterior bearing walls are estimated at I to 3 kips per lineal foot.
Column loads are estimated to range from 5 to 15 kips. If structural loads exceed those stated above,
we should be notified so we may evaluate their impact on foundation settlement and bearing
capacity. Site development will include building pad preparation, underground utility installation,
street construction, and concrete driveway and sidewalk placement.
1.2 Purpose and Scope of Work
The purpose of this geotechnical study was to investigate the upper 51.5 feet of subsurface soil at
selected locations within the site for evaluation of physical/engineering properties. From the
subsequent field and laboratory data, professional opinions were developed and are provided in this
report regarding geotechnical conditions at this site and the effect on design and construction. The
scope of our services consisted of the following:
► Field exploration and in -situ testing of the site soils at selected locations and depths.
' ► Laboratory testing for physical and/or chemical properties of selected samples.
► Review of the available literature and publications pertaining to local geology,
faulting, and seismicity.
' ► Engineering analysis and evaluation of the data collected.
► Preparation of this report presenting our findings, professional opinions, and
' recommendations for the geotechnical aspects of project design and construction.
► In -situ testing of soil infiltration for stormwater retention basin.
Landmark Consultants, Inc. Page 1
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
This report addresses the following geotechnical issues:
► Subsurface soil and groundwater conditions
► Site geology, regional faulting and seismicity, near source factors, and site seismic
accelerations
Aggressive soil conditions to metals and concrete
► Soil infiltration rates of the native soil for stormwater retention basins
Professional opinions with regard to the above issues are presented for the following:
► Site grading and earthwork
► Building pad and foundation subgrade preparation
► Allowable soil bearing pressures and expected settlements
► Concrete slabs -on -grade
► Lateral earth pressures
► Excavation conditions and buried utility installations
► Mitigation of the potential effects of salt concentrations in native soil to concrete
mixes and steel reinforcement
► Seismic design parameters
► Pavement structural sections
Our scope of work for this report did not include an evaluation of the site for the presence of
environmentally hazardous materials or conditions.
1.3 Authorization
Mr. Jerry Green of RT. Hughes Co. LLC provided authorization by written agreement to proceed
with our work on April 13, 2005. We conducted our work according to our written proposal dated
April 13, 2005
Landmark Consultants, Inc. Page 2
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Section 2
METHODS OF INVESTIGATION
2.1 Field Exploration
Subsurface exploration was performed on April 22, 2005 using Williams Drilling of Indio, California
to advance three (3) borings to depths of 14.0 to 51.5 feet below existing ground surface. The
borings were advanced with a truck - mounted, CME 55 drill rig using 8 -inch diameter, hollow -stem,
continuous -flight augers. The approximate boring locations were established in the field and plotted
on the site map by sighting to discernable site features. The boring locations are shown on the Site
and Exploration Plan (Plate A -2).
A staff geologist observed the drilling operations and maintained a log of the soil encountered and
sampling depths, visually classified the soil encountered during drilling in accordance with the
Unified Soil Classification System, and obtained drive tube and bulk samples of the subsurface
materials at selected intervals. Relatively undisturbed soil samples were retrieved using a 2 -inch
outside diameter (OD) split -spoon sampler or a 3 -inch OD Modified California Split - Barrel (ring)
sampler. The samples were obtained by driving the sampler ahead of the auger tip at selected depths.
The drill rig was equipped with a 140 -pound CME automatic hammer for conducting Standard
Penetration Tests (SPT). The number of blows required to drive the samplers the last 12 inches of an
18 inch drive length into the soil is recorded on the boring logs as "blows per foot ". Blow counts (N
values) reported on the boring logs represent the field blow counts. No corrections have been
applied for effects of overburden pressure, automatic hammer drive energy, drill rod lengths, liners,
and sampler diameter.
After logging and sampling the soil, the exploratory borings were backfilled with the excavated
material. The backfill was loosely placed and was not compacted to the requirements specified for
engineered fill.
The subsurface logs are presented on Plates B -1 through B -3 in Appendix B. A key to the log
symbols is presented on Plate B -4. The stratification lines shown on the subsurface logs represent
the approximate boundaries between the various strata. However, the transition from one stratum to
another may be gradual over some range of depth.
Landmark Consultants, Inc. Page 3
Il
I
!1
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
2.2 Laboratory Testing
Laboratory tests were conducted on selected bulk and relatively undisturbed soil samples to aid in
classification and evaluation of selected engineering properties of the site soils. The tests were
conducted in general conformance to the procedures of the American Society for Testing and
Materials (ASTM) or other standardized methods as referenced below. The laboratory testing
program consisted of the following tests:
► Particle Size Analyses (ASTM D422) — used for soil classification and liquefaction
evaluation.
► Unit Dry Densities (ASTM D2937) and Moisture Contents (ASTM D2216) — used for
insitu soil parameters.
► Collapse Potential (ASTM D5333) — used for hydroconsolidation potential evaluation.
► Moisture - Density Relationship (ASTM D1557) — used for soil compaction determinations.
► Chemical Analyses (soluble sulfates & chlorides, pH, and resistivity) (Caltrans Methods) —
used for concrete mix evaluations and corrosion protection requirements.
The laboratory test results are presented on the subsurface logs and on Plates C -1 through C -4 in
Appendix C.
Landmark Consultants, Inc. Page 4
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Section 3
DISCUSSION
3.1 Site Conditions
The 23 -acre project site is relatively flat - lying, triangular in shape and is currently vacant desert land.
Thick vegetation, consisting of mesquite, desert flowers, tall grasses and other large bushes cover the
site. The All American Canal, approximately 30 feet above the surrounding area, is located along the
western boundary of the site. The site is bounded to the north by Avenue 60, a rural dirt road.
Adjacent properties are flat -lying and are approximately at the same elevation with this site. A single
family residence and vacant desert land are located across Avenue 60 to the north. To the east is a
single family residential community currently under development.
The project site lies at an elevation of approximately 30 feet below mean sea level (MSL) in the
Coachella Valley region of the California low desert. Annual rainfall in this and region is less than 4
inches per year with four months of average summertime temperatures above 100 °F. Winter
temperatures are mild, seldom reaching freezing.
3.2 Geologic Setting
The project site is located in the Coachella Valley portion of the Salton Trough physiographic
province. The Salton Trough is a geologic structural depression resulting from large scale regional
faulting. The trough is bounded on the northeast by the San Andreas Fault and Chocolate Mountains
and the southwest by the Peninsular Range and faults of the San Jacinto Fault Zone. The Salton
Trough represents the northward extension of the Gulf of California, containing both marine and
non -marine sediments since the Miocene Epoch. Tectonic activity that formed the trough continues
at a high rate as evidenced by deformed young sedimentary deposits and high levels of seismicity.
Figure 1 shows the location of the site in relation to regional faults and physiographic features. '
The surrounding regional geology includes the Peninsular Ranges (Santa Rosa and San Jacinto
Mountains) to the south and west, the Salton Basin to the southeast, and the Transverse Ranges
Landmark Consultants, Inc. Page 5
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
(Little San Bernardino and Orocopia Mountains) to the north and east. Hundreds of feet to several
thousand feet of Quaternary fluvial, lacustrine, and aeolian soil deposits underlay the Coachella
Valley.
The southeastern part of the Coachella Valley lies below sea level. In the.geologic past, the ancient
Lake Cahuilla submerged the area. Calcareous tufa deposits may be observed along the ancient
shoreline as high as elevation 45 to 50 feet MSL along the Santa Rosa Mountains from La Quinta
southward. Lacustrine (lake bed) deposits comprise the subsurface soils over much of the eastern
Coachella Valley with alluvial outwash along the flanks of the valley.
3.3 Seismicity and Faulting
Faulting and Seismic Sources: We have performed a computer -aided search of known faults or
seismic zones that lie within a 62 mile (100 kilometers) radius of the project site as shown on Figure
1 and Table 1. The search identifies known faults within this distance and computes deterministic
ground accelerations at the site based on the maximum credible earthquake expected on each of the
faults and the distance from the fault to the site. The Maximum Magnitude Earthquake (Mmax)
listed was taken from published geologic information available for each fault (CDMG OFR 96 -08
and Jennings, 1994).
Seismic Risk: The project site is located in the seismically active Coachella Valley of southern
California and is considered likely to be subjected to moderate to strong ground motion from
earthquakes in the region. The proposed site structures should be designed in accordance with the
California Building Code for near source factors derived from a "Design Basis Earthquake" (DBE).
The DBE is defined as the motion having a 10 percent probability of being exceeded in 50 years.
Seismic Hazards.
► Gooundshaking. The primary seismic hazard at the project site is the potential for strong
groundshaking during earthquakes along the San Andreas Fault. A further discussion of
groundshaking follows in Section 3.4.
P. Surface Rupture. The project site does not lie within a State of California, Alquist -Priolo
Earthquake Fault Zone. Surface fault rupture is considered to be unlikely at the project site because
of the well - delineated fault lines through the Coachella Valley as shown on USGS and CDMG maps.
Landmark Consultants, Inc. Page 6
Proposed Coral Mountain Estates - La Quinta, CA LCI Report No. LP05098
30.75
34.50
34.25
34.00
33.75
MAP OF REGIONAL FAULTS AND SEISMICITY
llliJ116.4 A, (82) 7.3 071 (92)
JPos
Redia7ds
El 4l1NM
Legends to Faufts:
BC:
Blue Cut
BM:
Borrego Mountain
BSZ:
Brawley Seismic Zone
CC:
Coyote Creek
CN:
Calico- Newberry
EL:
Elmore Ranch
ELS:
Elsinore
EM -C:
Emerson- Copper Mtn.
EP:
Eureka Peak
H:
Helendale
HS -B
Hot Springs -Buck Ridge
JV:
Johnson Valley
IM::
Imperial
M:
Morongo
ML:
Mesquite Lake
NF:
North Frontal Zone
OWS:
Old Woman Springs
P -B:
Pisgah - Bullion
PM
Pinto Mtn
SA:
San Andreas
SG-B:
San Gorgonio- Banning
SH:
Superstiition Hills
SJ:
San Jacinto
6.2 A.`W"iq V ~yJ 16.1 J(92)
291T' 6.5 "'(48)
Palm Dings RIVERSIDE CO.
n
�l � t
Sa acrnto Palm Desert
La Quinta
Project Site
5.�a L,(laso)
Salton
-\ Sea
Landmark Consultants, Inc.
115.75
Proposed Coral Mountain Estates - La Quinta, CA LCI Report No. LP05098
Fable 1
FAULT PARAMETERS & DEFERMONISFIC
ESTIMATES
OF PEAK GROUND AGGF.LEll
ATION8 PUA
Distance
Maximum
Avg
Avg
Data of
Largest
Est
Fault Nance or
(mi) &
Fault
Fault
Magnitude
Slip'
Return
Last
Historic
Site
Seismic Zone
Direction
Type
Length
Mmax
Rate
Period
Rupture
Event
PGA
from Site
km
Mw
m r
rs
ear
>5.5A19 ear
Reference Notes: 1
2
3
2
4
3
3
3
5
6
San Andreas Fault System
'
- Coachella Valley
8.9 NE
A
A
95
7.4
25
220
1690 + /-
6.5 1948
0.32
- San Gorgonio - Banning
12 N
A
A
98
7.4
10
--
1690 + /-
6.2 1986
0.26
- San Bernardino Mtn
31 NW
A
A
107
7.3
24
433
1812
6.5 1812
0.12
- Whole S. Calif. Zone
8.9 NE
A
A
345
7.9
-
--
1857
7.8 1857
0.41
San Jacinto Fault System
- Hot Spgs -Buck Ridge
13 SSW
B
A
70
6.5
2
354
6.3 1937
0.16
- Anza Segment
16 SSW
A
A
90
7.2
12
250
1918
6.8 1918
0.19
- Coyote Creek
19 SW
B
A
40
6.8
4
175
1968
6.5 1968
0.14
- Borrego Mtn
29 S
B
A
29
6.6
4
175
6.5 1942
0.09
- San Jacinto Valley
39 W
B
A
42
6.9
12
83
6.8 1899
0.08
- Elmore Ranch
43 ESE
B
A
29
6.6
1
225
1987
5.9 1987
0.06 ,
- Superstition Mtn.
46 SSE
B
A
23
6.6
5
500
1440+/-
0.06
- Superstition Hills
47 SE.
B
A
22
6.6
4
250
1987
6.5 1987
0.06
- Whole Zone
18 WSW
A
A
245
7.5
---
--
0.20
Mojave Faults
Blue Cut
20 N
B
C
30
6.8
1
762
0.13
Eureka Peak
24 N
C
C
19
6.4
0.6
5,000
1992
6.1 1992
0.09
Burnt Mtn
24 NNW
B
C
20
6.4
0.6
5,000
1992
7.3 1992
0.09
Morongo
35 NW
C
C
23
6.5
0.6
1,172
5.5 1947
0.07
Pinto Mountain
36 NNW
B
B
73
7.0
2.5
499
0.09
Bullion Mtn - Mesquite Lk.
37 NNE
B
C
88
7.0
0.6
5,000
0.09
S. Emerson- Copper Mtn.
38 N
B
C
54
6.9
0.6
5,000
0.08
Landers
39 NNW
B
C
83
7.3
0.6
5,000
1992
7.3 1992
0.10
N. Johnson Valley
49 NNW
B
C
36
6.7
0.6
5,000
0.06
North Frontal Fault Z. (E)
50 NNW
B
C
27
6.7
0.5
1,727
0.07
Notes:
1. Jennings (1994) and CDMG (1996)
2. CDMG (1996), where Type A faults - slip rate >5 mm/yr and well constrained paleoseismic data
Type B faults - all other faults.
3. WGCEP (1995)
4. CDMG (1996) based on Wells & Coppersmith (1994)
5. Ellsworth Catalog in USGS PP 1515 (1990) and USBR (1976), MW = moment magnitude,
6. The deterministic estimates of the Site PGA are based on the attenuation relationship of:
Boore, Joyner, Fumal (1997)
Landmark Consultants, Inc..
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
However, because of the high tectonic activity and deep alluvium of the region, we cannot preclude
the potential for surface rupture on undiscovered or new faults that may underlie the site..
► Liquefaction. Liquefaction is unlikely to be a potential hazard at the site since the groundwater is.
deeper than 50 feet (the maximum depth that liquefaction is known to occur).
Other Secondary Hazards.
► Landsliding. The hazard of landsliding is unlikely due to the regional planar topography. No
ancient landslides are shown on geologic maps of the region and no indications of landslides were
observed during our site investigation.
► Volcanic hazards. The site is not located in proximity to any known volcanically active area and
the risk of volcanic hazards is considered very low.
P. Tsunamis, seiches, and flooding. The site does not lie near any large bodies of water, so the
threat of tsunami, seiches, or other seismically - induced flooding is unlikely. The site is located down
gradient from the All American Canal. If rupture of the canal were to occur due to seismic events,
flooding of the site is possible.
3.4 Site Acceleration and CBC Seismic Coefficients
Site Acceleration: Deterministic horizontal peak ground accelerations (PGA) from maximum
probable earthquakes on regional faults have been estimated and are included in Table 1. Ground
motions are dependent primarily on the earthquake magnitude and distance to the seismogenic
(rupture) zone. Accelerations also are dependent upon attenuation by rock and soil deposits,
direction of rupture and type of fault; therefore, ground motions may vary considerably in the same
general area.
We have used the computer program FRISKSP (Blake, 2000) to provide a probabilistic estimate of
the site PGA using the attenuation relationship of Boore, Joyner, and Fumal (1997) Soil (310). The
PGA estimate for the project site having a 10% probability of occurrence in 50 years (return period
of 475 years) is 0.55g.
CBC Seismic Coefficients: The CBC seismic response coefficients are calculated from the near-
source factors for Seismic Zone 4. The near - source factors are based on the distance from the fault
Landmark Consultants, Inc. Page 7
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
and the seismic source type. The following table lists seismic and site coefficients (near source
factors) determined by Chapter 16 of the 2001 CBC. This site lies within 14.3 km of a Type A fault
overlying So (stifJ) soil.
CBC Seismic Coefficients for Chapter 16 Seismic Provisions
3.5 Subsurface Soil
Subsurface soils encountered during the field exploration conducted on April 22, 2005 consist of
medium dense to dense interbedded silty sands and sandy silts. The subsurface logs (Plates B -1
through B -3) depict the stratigraphic relationships of the various soil types.
3.6 Groundwater
Groundwater was not encountered in the borings during the time of exploration and is deeper than 50
' feet below ground surface at this site. There is uncertainty in the accuracy of short-term water level
measurements, particularly in fine- grained soil. Groundwater levels may fluctuate with precipitation,
irrigation of adjacent properties, drainage, and site grading. The groundwater level noted should not
be interpreted to represent an accurate or permanent condition.
I1 3.7 Hydroconsolidation
' In and climatic regions, granular soils have a potential to collapse upon wetting. This collapse
(hydroconsolidation) phenomenon is the result of the lubrication of soluble cements (carbonates) in
the soil matrix causing the soil to densify from its loose configuration during deposition.
Landmark Consultants, Inc. Page 8
Seismic
Distance to
Near Source Factors
Seismic Coefficients
CBC Code
Soil Profile
Edition
Type
Source
Critical
Type
Source
Na
Nv
Ca
Cv
2001
SD
A
< 14.3 km
1.00
1.03
0.44
0.66
(stiff soil)
Ref. Table
16 -J
16 -U
- --
3.5 Subsurface Soil
Subsurface soils encountered during the field exploration conducted on April 22, 2005 consist of
medium dense to dense interbedded silty sands and sandy silts. The subsurface logs (Plates B -1
through B -3) depict the stratigraphic relationships of the various soil types.
3.6 Groundwater
Groundwater was not encountered in the borings during the time of exploration and is deeper than 50
' feet below ground surface at this site. There is uncertainty in the accuracy of short-term water level
measurements, particularly in fine- grained soil. Groundwater levels may fluctuate with precipitation,
irrigation of adjacent properties, drainage, and site grading. The groundwater level noted should not
be interpreted to represent an accurate or permanent condition.
I1 3.7 Hydroconsolidation
' In and climatic regions, granular soils have a potential to collapse upon wetting. This collapse
(hydroconsolidation) phenomenon is the result of the lubrication of soluble cements (carbonates) in
the soil matrix causing the soil to densify from its loose configuration during deposition.
Landmark Consultants, Inc. Page 8
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Collapse potential test indicated a slight risk of collapse upon inundation indicating at the project
site. Therefore, building foundations are not required to include provisions for mitigating the
hydroconsolidation caused by soil saturation from landscape irrigation or broken utility lines.
3.8 Soil Infiltration Rate
A total of two (2) infiltration tests were conducted on May 24, 2005 at the proposed location for the
stormwater retention basin as shown on the Site and Exploration Plan (Plate A -2). The tests were
performed using pipes inside 6 -inch diameter hand auger boreholes made to depths of approximately
3 feet below the existing ground surface, corresponding to the anticipated bottom depth of the
stormwater retention basin. The pipes were presoaked and filled with water and successive readings
of drop in water levels were made for a total elapsed time of 360 minutes, until a stabilization drop
was recorded.
A soil infiltration rate of 3 -5 gallons per hour per square foot of bottom area may be used for
infiltration design. An oil /water separator should be installed at inlets to the stormwater retention
basin to prevent sealing of the basin bottom with silt and oil residues.
We recommend additional testing should be performed after the completion of rough grading
operations, to verify the soil infiltration rate.
Landmark Consultants, Inc. Page 9
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Section 4
RECOMMENDATIONS
4.1 Site Preparation
Clearing and Grubbing_ All surface improvements, debris or vegetation including grass, trees, and
weeds on the site at the time of construction should be removed from the construction area. Root
balls should be completely excavated. Organic strippings should be hauled from the site and not
used as fill. Any trash, construction debris, concrete slabs, old pavement, landfill, and buried
obstructions such as old foundations and utility lines exposed during rough grading should be traced
to the limits of the foreign material by the grading contractor and removed under our supervision.
Any excavations resulting from site clearing should be dish - shaped to the lowest depth of
disturbance and backfilled under the observation of the geotechnical engineer's representative.
Building Pad Preparation: The existing surface soil within the building pad areas should be removed
to 36 inches below the existing grade or 18 inches below the lowest foundation grade (whichever is
lower) extending five feet beyond all exterior wall/column lines (including adjacent concreted areas).
Exposed subgrade should be scarified to a depth of 12 inches, uniformly moisture conditioned to f
2% and recompacted to a minimum of 90% of the maximum density determined in accordance with
ASTM D 1557 Methods.
The native soil is suitable for use as engineered fill provided it is free from concentrations of organic
matter or other deleterious material. The fill soil should be uniformly moisture conditioned by
discing and watering to the limits specified above, placed in maximum 8 -inch lifts (loose), and
compacted to the limits specified above.
Imported fill soil (if required) should be similar to onsite soil or non - expansive, granular soil meeting
the USCS classifications of SM, SP- SM,'or SW -SM with a maximum rock size of 3 inches. The
geotechnical engineer should approve imported fill soil sources before hauling material to the site.
Imported granular fill should be placed in lifts no greater than 8 inches in loose thickness and
compacted to a minimum of 90% of ASTM D1557 maximum dry density at optimum moisture ±2 %.
In areas other than the building pad which are to receive area concrete slabs, the ground surface
should be scarified to 12 inches, moisture conditioned to at optimum moisture ±2% and recompacted
to a minimum of 90% of ASTM D1557 maximum density just prior to concrete placement.
Landmark Consultants, Inc. Page 10
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Trench Backfill: On -site soil free of debris, vegetation, and other deleterious matter may be suitable
for use as utility trench backfill. Backfill soil within roadways should be placed in layers not more
than 6 inches in thickness and mechanically compacted to a minimum of 90% of the ASTM D 1557
maximum dry density except for the top 12 inches of the trench which shall be compacted to at least
90 %. Native backfill should only be placed and compacted after encapsulating buried pipes with
suitable bedding and pipe envelope material. Pipe envelopeibedding should either be clean sand
(Sand Equivalent SE>30) or crushed rock when encountering groundwater. A geotextile filter fabric
(Mirafi 140N or equivalent) should be used to encapsulate the crushed rock to reduce the potential
for in- washing of fines into the gravel void space. Precautions should be taken in the compaction of
the backfill to avoid damage to the pipes and structures.
Moisture Control and Drainage: The moisture condition of the building pad should be maintained
during trenching and utility installation until concrete is placed or should be rewetted before
initiating delayed construction.
Adequate site drainage is essential to future performance of the project. Infiltration of excess
irrigation water and storm waters can adversely affect the performance of the subsurface soil at the
site. Positive drainage should be maintained away from all structures (5% for 5 feet minimum across
unpaved areas) to prevent ponding and subsequent saturation of the native clay soil. Gutters and
downspouts may be considered as a means to convey water away from foundations. If landscape
irrigation is allowed next to the building, drip irrigation systems or lined planter boxes should be
used. The subgrade soil should be maintained in a moist, but not saturated state, and not allowed to
dry out. Drainage should be maintained without ponding.
Observation and Density Testing: All site preparation and fill placement should be continuously
observed and tested by a representative. of a qualified geotechnical engineering firm. Full -time
observation services during the excavation and scarification process is necessary to detect
undesirable materials or conditions and soft areas that may be encountered in the construction area.
The geotechnical firm that provides observation and testing during construction shall assume the
responsibility of " geotechnical engineer of record' and, as such, shall perform additional tests and
investigation as necessary to satisfy themselves as to the site conditions and the recommendations for
site development.
Landmark Consultants, Inc. Page 11
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Auxiliary Structures Foundation Preparation: Auxiliary structures such as free standing or retaining
walls should have the existing soil beneath the structure foundation prepared in the manner
recommended for the building pad except the preparation needed only to extend 18 inches below and
beyond the footing.
4.2 Foundations and Settlements
Shallow spread footings and continuous wall footings are suitable to support the structures provided
they are structurally tied with grade -beams to resist differential movement. Footings shall be
founded on a layer of properly prepared and compacted soil as described in Section 4.1. The
foundations may be designed using an allowable soil bearing pressure of 1,500 psf. The allowable
soil pressure may be increased by 20% for each foot of embedment depth in excess of 18 inches and
by one -third for short term loads induced by winds or seismic events. The maximum allowable soil
pressure at increased embedment depths shall not exceed 2,500 psf.
All exterior and interior foundations should be embedded a minimum of 18 inches below the
building support pad or lowest adjacent final grade, whichever is deeper. Interior footings may be 12
inches deep. Continuous wall footings should have a minimum width of 12 inches. Spread footings
should have a minimum dimension of 24 inches. Recommended concrete reinforcement and sizing
for all footings should be provided by the structural engineer.
Resistance to horizontal loads will be developed by passive earth pressure on the sides of footings
and frictional resistance developed-along the bases of footings and concrete slabs. Passive resistance
to lateral earth pressure may be calculated using an equivalent fluid pressure of 300 pcf for sands to
resist lateral loadings. The top one foot of embedment should not be considered in computing
passive resistance unless the adjacent area is confined by a slab or pavement. An allowable friction
coefficient of 0.35 for sands may also be used at the base of the footings to resist lateral loading.
Foundation movement under the estimated static (non - seismic) loadings and static site conditions are
estimated to not exceed' /4 inch with differential movement of about two- thirds of total movement for
the loading assumptions stated above when the subgrade preparation guidelines given above are
followed.
1 Landmark Consultants, Inc. Page 12
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
4.3 Slabs -On -Grade
Concrete slabs and flatwork should be a minimum of 4 inches thick. Concrete floor slabs may either
be monolithically placed with the foundation or dowelled after footing placement. The concrete
slabs may be placed on granular subgrade that has been compacted at least 90% relative compaction
(ASTM D1557) and moistened to near optimum moisture just before the concrete placement
To provide protection against vapor or water transmission through the slabs, we recommend that the
slabs -on -grade be underlain by a layer of clean concrete sand at least 4 inches thick. To provide
additional protection against water vapor transmission through the slab in areas where vinyl or other
moisture- sensitive floor covering is planned, we recommend that a 10 -mil thick impermeable plastic
membrane (visqueen) be placed at mid - height within the sand layer. The vapor inhibitor should be
installed in accordance with the manufacturer's instructions. We recommend that at least a 2 -foot
lap be provided at the membrane edges or that the edges be sealed.
Concrete slab and flatwork reinforcement should consist of chaired rebar slab reinforcement
(minimum of No. 4 bars at 18 -inch centers, both horizontal directions) placed at slab mid - height to
resist potential swell forces and cracking. Slab thickness and steel reinforcement are minimums only
and should be verified by the structural engineer /designer knowing the actual project loadings. All
steel components of the foundation system should be protected from corrosion by maintaining a 3-
inch minimum concrete cover of densely consolidated concrete at footings (by use of a vibrator).
The construction joint between the foundation and any mowstrips /sidewalks placed adjacent to
foundations should be sealed with a polyurethane based non - hardening sealant to prevent moisture
migration between the joint. Epoxy coated embedded steel components or permanent waterproofing
membranes placed at the exterior footing sidewall may also be used to mitigate the corrosion
potential of concrete placed in contact with native soil.
Control joints should be provided in all concrete slabs -on -grade at a maximum spacing (in feet) of 2
to 3 times the slab thickness (in inches) as recommended by American Concrete Institute (ACI)
guidelines. All joints should form approximately square patterns to reduce randomly oriented
contraction cracks. Contraction joints in the slabs should be tooled at the time of the pour or sawcut
(1/4 of slab depth) within 6 to 8 hours of concrete placement. Construction (cold) joints in
foundations and area flatwork should either be thickened butt joints with dowels or a thickened
keyed joint designed to resist vertical deflection at the joint. All joints in flatwork should be sealed
Landmark Consultants, Inc. Page 13
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
to prevent moisture, vermin, or foreign material intrusion. Precautions should be taken to prevent
curling of slabs in this and desert region (refer to ACI guidelines).
All independent flatwork (sidewalks, driveways, patios) should be underlain by 2 inches of concrete
sand or aggregate base, dowelled to the perimeter foundations where adjacent to the building and
sloped 2% or more away from the building. A minimum of 24 inches of moisture conditioned (2%
minimum above optimum) and compacted subgrade (90 %) and a 10 -mil (minimum) polyethylene
separation should underlie the flatwork containing steel reinforcing (except wire mesh). All flatwork
should be jointed in square patterns and at irregularities in shape at a maximum spacing of 10 feet or
the least width of the sidewalk. Driveway slabs should have a thickened edge extending a minimum
of 4 inches below a 4 -inch sand or aggregate base course which should be compacted to a minimum
of 90% of ASTM D1557 maximum density.
4.4 Concrete Mixes and Corrosivity
Selected chemical analyses for corrosivity were conducted on bulk samples of the near surface soil
from the project site (Plate C -4). The native soils have low level of sulfate ion concentration (212
ppm). Sulfate ions in high concentrations can attack the cementitious material in concrete, causing
weakening of the cement matrix and eventual deterioration by raveling.
A minimum of 2,500 psi concrete of Type II Portland Cement with a maximum water /cement ratio
of 0.60 (by weight) should be used for concrete placed in contact with native soil on this project
(sitework including streets, sidewalks, driveways, patios, and foundations).
The native soil has moderate level of chloride ion concentration (260 ppm). Chloride ions can cause
corrosion of reinforcing steel, anchor bolts and other buried metallic conduits. Resistivity
determinations on the soil indicate severe potential for metal loss because of electrochemical
corrosion processes. Mitigation of the corrosion of steel can be achieved by using steel pipes coated
with epoxy corrosion inhibitors, asphaltic and epoxy coatings, cathodic protection or by
encapsulating the portion of the pipe lying above groundwater with a minimum of 3 inches of
densely consolidated concrete. No metallic pipes or conduits should be placed below foundations.
Landmark Consultants, Inc. Page 14
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Foundation designs shall provide a minimum concrete cover of three (3) inches around steel
reinforcing or embedded components (anchor bolts, hold - downs, etc.) exposed to native soil or
landscape water (to 18 inches above grade). If the 3 -inch concrete edge distance cannot be achieved,
all embedded steel components (anchor bolts, hold - downs, etc.) shall be epoxy dipped for corrosion
protection or a corrosion inhibitor and a permanent waterproofing membrane shall be placed along
the exterior face of the exterior footings. Additionally, the concrete should be thoroughly vibrated at
footings during placement to decrease the permeability of the concrete.
4.5 Excavations
All site excavations should conform to CalOSHA requirements for Type C soil. The contractor is
solely responsible for the safety of workers entering trenches. Temporary excavations with depths of
4 feet or less may be cut nearly vertical for short duration. Temporary slopes should be no steeper
than'l.5:1 (horizontal:vertical). Sandy soil slopes should be kept moist, but not saturated, to reduce
the potential of raveling or sloughing.
Excavations deeper than 4 feet will require shoring or slope inclinations in conformance to
CAL /OSHA regulations for Type C soil. Surcharge loads of stockpiled soil or construction materials
should be set back from the top of the slope a minimum distance equal to the height of the slope. All
permanent slopes should not be steeper than 3:1 to reduce wind and rain erosion. Protected slopes
with ground cover may be as steep as 2:1. However, maintenance with motorized equipment may
not be possible at this inclination.
4.6 Lateral Earth Pressures
Earth retaining structures, such as retaining walls, should be designed to resist the soil pressure
imposed by the retained soil mass. Walls with granular drained backfill may be designed for an
assumed static earth pressure equivalent to that exerted by a fluid weighing 35 pcf for unrestrained
(active) conditions (able to rotate 0.1 % of wall height), and 55 pcf for restrained (at -rest) conditions.
These values should be verified at the actual wall locations during construction.
Landmark Consultants, Inc. Page 15
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
When applicable seismic earth pressure on walls may be assumed to exert a uniform pressure
distribution of 7.5H psf against the back of the wall, where H is the height of the backfill. The total
seismic load is assumed to act as a point load at 0.6H above the base of the wall.
Surcharge loads should be considered if loads are applied within a zone between the face of the wall
and a plane projected behind the wall 45 degrees upward from the base of the wall. The increase in
lateral earth pressure acting uniformly against the back of the wall should be taken as 50% of the
surcharge load within this zone. Areas of the retaining wall subjected to traffic loads should be
designed for a uniform surcharge load equivalent to two feet of native soil.
Walls should be provided with backdrains to reduce the potential for the buildup of hydrostatic
pressure. The drainage system should consist of a composite HDPE drainage panel or a 2 -foot wide
zone of free draining crushed rock placed adjacent to the wall and extending 2/3 the height of the
wall. The gravel should be completely enclosed in an approved filter fabric to separate the gravel
and backfill soil. A perforated pipe should be placed perforations down at the base of the permeable
material at least six inches below finished floor elevations. The pipe should be sloped to drain to an
appropriate outlet that is protected against erosion. Walls should be properly waterproofed. The
project geotechnical engineer should approve any alternative drain system.
4.7 Seismic Design
This site is located in the seismically active southern California area and the site structures are
subject to strong ground shaking due to potential fault movements along the San Andreas Fault.
Engineered design and earthquake- resistant construction are the common solutions to increase safety
and development of seismic areas. Designs should comply with the latest edition of the CBC for
Seismic Zone 4 using the seismic coefficients given in Section 3.4 of this report. This site lies
within 14.3 km of a Type A fault overlying So (stiffi soil.
4.8 Pavements
Pavements should be designed according to CALTRANS or other acceptable methods. Traffic
indices were not provided by the project engineer or owner; therefore, we have provided structural
Landmark Consultants, Inc. Page 16
tProposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
' sections for several traffic indices for comparative evaluation. The public agency or design engineer
should decide the appropriate traffic index for the site. Maintenance of proper drainage is necessary
' to prolong the service life of the pavements. Based on the current State of California CALTRANS
method, an estimated R -value of 40 for the subgrade soil and assumed traffic indices, the following
� I
1
table provides our estimates for asphaltic concrete (AC) pavement sections.
RECOMMENDED PAVEMENTS SECTIONS
R -Value of Subarade Soil - 40 (estimated) Design Method - CALTRANS 1990
Notes:
1) Asphaltic concrete shall be Caltrans, Type B,' /4 inch maximum medium grading, (' /2 inch for
parking areas) compacted to a minimum of 95% of the 50 -blow Marshall density (ASTM
D1559).
2) Aggregate base shall conform to Caltrans Class 2 (3/4 in. maximum), compacted to a
minimum of 95% of ASTM D1557 maximum dry density.
3) Place pavements on 8 inches of moisture conditioned (minimum 4% above optimum) native
soil compacted to a minimum of 90% of the maximum dry density determined by ASTM
D1557.
Final recommended section may need to be based on sampling and R -Value testing during grading
operations when actual subgrade soils will be exposed.
Landmark Consultants, Inc. Page 17
Flexible Pavements
Asphaltic
Aggregate
Traffic
Concrete
Base
Index
Thickness
Thickness
(assumed)
(in.)
(in.)
5.0
3.0
4.5
6.0
3.5
6.0
7.0
4.5
6.5
8.0
5.0
8.5
Notes:
1) Asphaltic concrete shall be Caltrans, Type B,' /4 inch maximum medium grading, (' /2 inch for
parking areas) compacted to a minimum of 95% of the 50 -blow Marshall density (ASTM
D1559).
2) Aggregate base shall conform to Caltrans Class 2 (3/4 in. maximum), compacted to a
minimum of 95% of ASTM D1557 maximum dry density.
3) Place pavements on 8 inches of moisture conditioned (minimum 4% above optimum) native
soil compacted to a minimum of 90% of the maximum dry density determined by ASTM
D1557.
Final recommended section may need to be based on sampling and R -Value testing during grading
operations when actual subgrade soils will be exposed.
Landmark Consultants, Inc. Page 17
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
Section 5
LIMITATIONS AND ADDITIONAL SERVICES
5.1 Limitations
The recommendations and conclusions within this report are based on current information regarding
the proposed Coral Mountain Estates residential development located near the southwest corner of
Avenue 60 and Madison Street south of La Quinta, California. The conclusions and
recommendations of this report are invalid if:
► Structural loads change from those stated or the structures are relocated.
► The Additional Services section of this report is not followed.
► This report is used for adjacent or other property.
► Changes of grade or groundwater occur between the issuance of this report and
construction other than those anticipated in this report.
► Any other change that materially alters the project from that proposed at the time this
report was prepared.
Findings and recommendations in this report are based on selected points of field exploration,
geologic literature, laboratory testing, and our understanding of the proposed project. Our analysis of
data and recommendations presented herein are based on the assumption that soil conditions do not
vary significantly from those found at specific exploratory locations. Variations in soil conditions
can exist between and beyond the exploration points or groundwater elevations may change. If
detected, these conditions may require additional studies, consultation, and possible design revisions.
This report contains information that may be useful in the preparation of contract specifications.
However, the report is not worded is such a manner that we recommend its use as a construction
specification document without proper modification. The use of information contained in this
report for bidding purposes should be done at the contractor's option and risk.
This report was prepared according to the generally accepted geotechnical engineering standards of
practice that existed in Riverside County at the time the report was prepared. No express or implied
warranties are made in connection with our services. This report should be considered invalid for
periods after two years from the report date without a review of the validity of the findings and
recommendations by our firm, because of potential changes in the Geotechnical Engineering
Standards of Practice.
Landmark Consultants, Inc. Page 18
Proposed Coral Mountain Estates — La Quinta, CA LCI Report No. LP05098
The client has responsibility to see that all parties to the project including, designer, contractor, and
subcontractor are made aware of this entire report. The use of information contained in this report
for bidding purposes should be done at the contractor's option and risk.
5.2 Additional Services
We recommend that Landmark Consultants, Inc. be retained as the geotechnical consultant to
provide the tests and observations services during construction. If Landmark Consultants does not
provide such services then the geotechnical engineeringfirm providing such tests and observations
shall become the geotechnical engineer of record and assume responsibility for the project.
The recommendations presented in this report are based on the assumption that:
► Consultation during development of design and construction documents to check that the
geotechnical recommendations are appropriate for the proposed project and that the
geotechnical recommendations are properly interpreted and incorporated into the
documents.
► Landmark Consultants will have the opportunity to review and comment on the plans and
specifications for the project prior to the issuance of such for bidding.
► Continuous observation, inspection, and testing by the geotechnical consultant of record
during site clearing, grading, excavation, placement of fills, building pad and subgrade
preparation, and backfilling of utility trenches.
► Observation of foundation excavations and reinforcing steel before concrete placement.
► Other consultation as necessary during design and construction.
We emphasize our review of the project plans and specifications to check for compatibility with our
recommendations and conclusions. Additional information concerning the scope and cost of these
services can be obtained from our office.
Landmark Consultants, Inc. Page 19
! 'vxr !40 � 9f' ral,r!!.:wla:�csra�cF�
f �� /yr��y,lt.3 }_.fw.... `- .6,.k.
t `� '.?�i�+'"''iiq:Vi'u ~ \, 'v €;..::dt ? :..
;!f •• . `f F >. i:Y -J }'KJ'?u "'�1.�'S':{ t' ,�F 1C
•
T %
gtN:n an-a! - 5'i �s.:, la 11 2f n,ye. 3r�s �. "�` ...' " °_�,.•: tg:.... •§sue yyt,f v:po; .. ?'es�r
F—'uL;!"St:'t
fy
x ')*
��N'.y�,.,`Y . ``t ~�"��^�.,^;,� ., = —��=„' 7,;�0 •.wit,. ' f�s�� /; -.. ':�` �
` ze fie..
a,z
,
G3cFf{".�3 ?'t
R.
:.,:
_
'8�"33g�T,.��� �!� ...�� '�= :ieT•i x.s::P+, x, !n� °`I:t:, -. .r'?" .i {, �[t`ra<,rY�� .. .1 4'" \,a �� �.�._._.- .,
&9 eb..... r > :4�',,s• ._ •y.; \;r.
Lo
...�,....�..: < y4,: v1.- i ��� � � ti Yf `'-:. �'cl.� , �,�a. £'." ��''Fr "s:��' a� V4' zi. Prtiw, ,i .,.,i•e... `� 'Y �, ��:,�
:., -:_. .y. f.'4 �.- '.= .if""`•,,''iC,:- ;:S �'i' !�: -so ;;.:sN s^._ � " o �.:>c• O� �
,'_A_� .:T'.:'':r�•S �: y! b"-'' \ a - ! � !��' ��Lf.�iit+'1�� - � '. rc F i✓�n � 4'�
i3Q,3 ;'`�.,';s
y..i 4� �:w -. �. .ITT �'� i�•:nji �H .= `^�,(� :ay�4A��:iM1S� 'X'i JS -FaY - td.�n v_ �q. � ': a'' r ` yhtP. �'.iY P4!. �
�,....P,a.g '�'''`i'f ,a� „ - � ' e'r ��`�"'�- �iY`zZ -_tc_�� "�t, � •` �' t�s
y
V/
N-
14
ds'.-` �,':',..:- t ^�k"�,ier,vnsy }•,�!,'yy�.�"rr._ -i � �._ .y �' -! � ''�1.� _ ^ -e - _ _,_. ?'�
td� `9..•t�
IYZAI”, Mix
Hk
AIM-
iVlE.1' E4iPti5:i',i �1P` vru
LANDMARK
Plate
Project No.: LP05098 Vicinity Map A -1
=r-
T.:
yy�
C ,ww
: ROMESS
i
LANDMARK
Plate
Project No.: LP05098 Vicinity Map A -1
z 7
7
ZIS.-
e7w-
-N.
.4i
Project Site
Legend
Approximate Boring Location (typ)
• Approximate Infiltration Test Location (typ)
LANDMARK
Plate
Project No.: LP05098 Site and Exploration Plan A-2 I
dC
33
J7RU
C
."ZCdC
Ou e
All
LANDMARK
Emmmmm=
' DWNW&W C-*-v USDA Soil Conservation Plate
Project No.: LP05098 Soil Service Map A-3
United States Department of Agzieuifure
Soil Conservation Service
in cooperation With
Uni-tiersity of' California AgricuOural Experiment
Station
� -Uqj Sul
rks
WO
sms as "an
}�0�*�/ aS v
vvs-ds��
0s-ds'���
Os
----'----------'
|-------------'^—|
| {
--_____—_____._'-�q"���
--------------- —~-----'������|
---
---------'
---------- ' sytms
------------ —
------------
Pugit --------'^--~-----pu�o���
'— SiqqOl4p^ CJ JA
Milo] 4putw
------------ n^�q^�"^pwn,!S^Jj',,a»12^/el�i |
----------------------- |
_--yvmmamg'pvvS
----------^^ ~ —`
J.
-----'—~--' —' ,CiqqctO
_Pin
__—_—_
------------- --------P«m/'ClIaA*D
---------puusealv«o
----------------------- yp*wx���
----------- puc
---'^---------~--^'—pulrs�
----'�-------------- p«v/Stnu»]
--------'^— ' tvvctj
----------
____________
pimill
�D,a < ! tteqj ssalmraw > 1*4WAS a-41)
`6 WWI
Ul
.ULjWIS MOSI
99
09-0
Vr-01
81-0
09+l1
!M-ZI
�vO��qnun�
''-''---�0] 0:)
'l3OnwmqonqJ
�r
S?-�
,
--''--]*�w]
09-0
.—''-''''''-'`'''~'—SMO
09-0
------------J4:)
/
� 01-V
----- `^--
0�'0
---------
|
'nv»p�O
n�-ur
� 01-0
------^----
1+-0
______ __
— --
0$-0
--------------- —'-''Op]
�uoV3
/ 0a-IC
|S~-�
C-0
^
--^'—^----- '-318
�
r—'---
'`----'-------tH
---------------------
Ul
.ULjWIS MOSI
99
CT.X
dX,
JIKI
-ax
f-aN,
a.15.1
MN
a1.
aM
d-9
4CI,NT.
a, K
aX
di
JIM,
dIN
C-alKi
xaCscri
L9
----------------------
---------------
O
Orr-9T
-of
sc99-OZ
'R
4
sIt-02-1
9--o
M-9
ot-M
*-o
Ot---9
01-0
O'l--G
N.--q
OT-0
01-0
0"
2
OSI-or
os--osl
cs-OL
05-919
OS-DS'
CT
'a --OF
W-09
MI-q?,
09-01,
q-•Oz
OL-of
U-se
01-Os
ft -02
Ms-r�
OCH)L
----------------
001
out
001 OUT
wl
001
GO-V
0 "-1 t
0 -Irjk
05-v.
)BT -Si
(B-ov
P L-oq
)OT-OR
OS- )2
)01-OS
os-� t
-------- I..-.--,.--- I ------------------ I-- - - - .. - ------- --- ..p- .--- ..-- ---- - --- ---
Pd
--- ----- ------
OOT
001
001
09-vtl
oo--�t
09-0V
09-c.lt
09-�f-
001-08
001-199
DOI-98
GOT—M
001--VIR
001-06
03-of
001-06
001
001,
OBT-06
A,
------ --- -
0 �,
0
09-9
09--s
M-Se
09-3
09-9
OT-0
91-0
OF-SI
0
0
OT-0
GE-07,
01-0
OZ-01
0
0
0
05-0
01
OZ--() -9
ul' 0
iFI JIM MXV blaawfdw.4
t2 t, a3ad '
ryaZicurqsa Tau axon stvuaw ,Lnua tru p zDvasqV
-vi'mawrm.) ')LYxTP.,oD %(UGMAII!
A
L-V 'g-V
L-V 'g-V
L-V 'Q-v
f-v
C-v 'Z-V 11
T—V
I4
•
------------- mrolArl* X11F, Isvp sips
qoHD - ------- ----- * ---------- Umol
U.'Vol A'J'a sIgs 1XVP A-2
grs
---- ----------- ------ txiucq
sul"T
•;aojpaq pajoqjramu�j I
Ike-as IM9 au:,j 1pays Sumol 1puvS
�vospaq paxalrvaAj
Ne ----------- muol Spun am
---------------------- j�oospaq
---------- ---------- rmvc
---------------
------------------------ *1 ----------
Ho "TO -------------- --------------- sula SIrls
lkvg� as 'IBS - -------------- ------ ____._ ,
PuIg
-------- --------------------- --- P'QUS OUIA
,mm,xvi wisn
ol
01-0
of
of-0
09--oz
U-0
09-TZ
TZ• O
m
f
i--o
09-of
OT-0
G"T
0 f.-O
090
o"
09_0�
09-S
V11
............................ s 1
:Uojjrs
-na
:pjvi eiqqnly.
EnTlamuivi.,idwol oilq.lrl
•n-d dcij*l.no lj-aou
.04
:don2no it3oll
-Ind d=ji.io ijaoU
------ - - -_- --Ind 1,jolmo.
jo
atu 0
----- SPN
'PU
I'M
----- ------ BDV,\, lopw a Pvv
:z:oto�&I,�r I
laud dozy no 3IDoU
I
,Vvd elaam-ams-dujol aMill
- -- i
Idl 1
wtd puviyaq1ti
Urm I U 1.2m 1
Do[ *,- -)tu I
-dD
----------------- - "YPJ
------ - - - - -V C) a qg lVqq
----------------------
ODD
UVUTUO
pint aar"a pos
• 1
------------ Pway.
11V
Spurs *muol, llis Iturol Sim- -Oull i�J,'A
1.111Z
,11,kT
----------- =al 4kpu"cs Dti'll jcaa'&
--ravol kpu-a lumol `wu6j /puvs atril &jai
Itts .... tavol fpuvs atn
------------
---------------- ----------------
11j.V%
MV01 fr'lo f.jt!s C04 pUv.- su'vool PaijilrAls,
I ilk,
11.0
-------------- ------ Muol I
--- ----- ---- - - - - -u mol sq;) Aqf!S
i IN!
STr sipsoa pUvGAum%M.l tilt
------- ---------- "Urml
Ilk N S
puts ou!'j
mvoj A 'VP Aps al pays swu 01 pil!jilialls
jk s
--
------------------------ (Emol P-jvs oul
.a
'11'4�
invol f"Glo Al L£ of pu" Stuvol
WS
,mm,xvi wisn
ol
01-0
of
of-0
09--oz
U-0
09-TZ
TZ• O
m
f
i--o
09-of
OT-0
G"T
0 f.-O
090
o"
09_0�
09-S
V11
............................ s 1
:Uojjrs
-na
:pjvi eiqqnly.
EnTlamuivi.,idwol oilq.lrl
•n-d dcij*l.no lj-aou
.04
:don2no it3oll
-Ind d=ji.io ijaoU
------ - - -_- --Ind 1,jolmo.
jo
atu 0
----- SPN
'PU
I'M
----- ------ BDV,\, lopw a Pvv
:z:oto�&I,�r I
laud dozy no 3IDoU
I
,Vvd elaam-ams-dujol aMill
- -- i
Idl 1
wtd puviyaq1ti
Urm I U 1.2m 1
Do[ *,- -)tu I
-dD
----------------- - "YPJ
------ - - - - -V C) a qg lVqq
----------------------
ODD
UVUTUO
pint aar"a pos
• 1
01--s
alk,
S-ax
C.-alki
ot-sz
a.N
vV-1CIV
-41
ak
JN,
drkl
S-a_>\
9-aX
sl- a X
S-4i'M
Si--u
st-m
<1 ?,%T
9-41K
OZ-01
ClK
9-&&T
di
dlK
In" put
fpus�sJd
09-f-It
09--tle
09-c-le
OE--PA I
S'6-11
96-eis
sle-11L
00--e
M-s
sz--sl Qt-.Q-Z.
sz--Sl I 0O--Dr
OL-St 1 96--06
----------------- VT-S
OL-iv
------------------ 9 1-11
-----------
oc-C-7
oll.-W
0£-151.
90-012
OD-ST
I
%--m
09-V I
99-Op
01-0s,
96-06
OL-09
M-06
---------- .........
o-os
oc-oz
06-OL
96-ss
001-0
09-OS
------------------
0"9
0"T
0
-------------
-------------
001
atnr
ptnbq
001-W
001-S6
001-06
C"L
08-09
OL-ST
01-09
001-56
99-M
09-99
O"S
001-08
001-09
9S-01
001
OOT
001-08
001-06
001-96
OOT-08
S;"L
001-08
C*S-OL
oot-09
08-OL
oot ov
001
001
OOT
001
001-ot
SL-4919
oot
001
001-9z
OOT
S6--S'L
001-08
001-09
001-SG
001-V6
001-96
OUT--S6
OOT
001
001-S6
001-96
001
001
001
ODI--96
OLII-96
001-S,6
001
69 YiNmoarivo .u.tmoo acusmAra
)OT 0
)OT
0
)01
0
)31
0
0
DOI 0
001
DOT-06
1 0
0
ON
OOT-06
0
0
001
0
00t 5L
0
001-3
0
0017916
0
001-0
0
o()j--G6
0
001
0
001
0
OOt
0
001
0
OOT
0
001
0
001
0
001
0
001
0
00,
0
ON
0
fed
panuquoD--iu,o.qvoypvM.0 puz
a JDUU
0 w m jo a-vm'!U-5,uur aq,4 pug pro[ aql So ants
".qt!,Os xulltals J.0 s4twulaxasleauu TIO Pme Ims aqj ul
p p jutu)m puz puts{ aill. jo stsvq m4.1 uo pa4uwi
.4sa
a. ..tjass aq, Sxaq.,,o -silos, .4uvw 30 apum
uit ,�pojz) paqxnjs!pun. jo 2utl-la-mt; zPqj jo quam.mis
M IrtolV - jj�og To Pia"I PLM I JoMtl
,JoqV,l ati'l Uj
J
TDppua4od
aqa:T.D-u4.7a Puv fulatu apo.LICID
Imna,,wd S4r puu 'jv,!aqvtu uollDnalsuoD vp sm pasn
414% _Sjjjj.qrjt_ m+t ItEoganpoi.d. don x 9 1.!os v 3:o S-vu�r
is a% spate 44lurlvS *11 alqq ut xraAig lanIT-A. Kfj,
III SC478OX-0, 1.4.4q) uy---) splaq pellplATpui. 10 .9jTujj:n -aq4
m.n. uot4taqddr, a;v,4vxa jo Sotvanbaq aq Sq puv
;,,ax. uot atp jo _.4qunb a-LI-1 Aq pajt�zjpa Si spr
.4v I . mg
FIMPUyPul J.o WI.Tuttus 4qL -SttTos Palv2paluou
I sans Rul
pl4jj,, tio p-,svq ain bsar4q=4
s
ratuqnlao :rats soquiTigua to *j,,)wV_,a uotre.m.lin atlt jo
FA,qzapuoa reauxPal'a aq sr passaad.va st Aj?.2q7.?.v3
'S[tOS 10 A,11AtS0,1403 a4l
-1 PuU ! MOTPOZIMIC10- uv 44 t X'-TOX '54uam
WTl,lrA,a u %,a
"We tlos buqvnreA� uf`'tLmoj;9;?q of sjtmjfl xaql.o ao
wald ivlua=uao 'sdoj;) aqj Vtql3alas ut jarlaod-wi
.40,4na'Al 110S SZSAjMv Sao'lnoqui Acl pBU!,im ue;)q
t
s011froA. Wq4 'T,!09 SUML! 10,1 -Zj-, qD pl;alj ATIMI
pas iaq
, sl. uortxolq xob= -qova So Hd ult a2ulu aqj,
nity-A I-ld m a2uvy. v ir passaadxa st um ova.,t V.,oS
M. 'a4cft U,0j4V2LT..TT TO *r Ut2r(Sap iT;l ut PUL UAW 2
a
sed'on to sou id 4,,o owoqz aq4 ut x0l3in jwqxodwl
f droaqvm. aj.qejj-eA.V -su.qzPoq tjolsx�daap auq
JaJUM, alqr[TUA-e aqj aSM 01 gfa3lff 1011 +a,tr t4atjd
. f400x-&ojjvq% -axn.V.)n.Tjs t.jos gum 'aimixal tios 'aal
Drudoao jo q.ua4uoD aav s;qj--!j
td. ajqvj=vAv 21 axmu Intu jalmm ploq o3 ffos
'I " so 41�lne aql wcalluml qvq j j!OS
Y g..:SSvq aq4 uo Palud St fl4pvd-vo J,4d-n aivu
-quatua2vuvat puv asn puel jo %aadsv aavljolum.
ux puv lsuta4sls pasods!p mtsv.m aaq4o pu.c sera s. s ltt
aj4dos aq sli'm ;o pigualod aqj '.l3u,q.vnjrAa ut Ismaq
-Sis aftuvaa,v ZUTU21-sap pall 2talluit'd 4q: pajaptsao
aq ol. ad4onej juv4aodtur ur st 1!os aqj jo AlqfqvaLuaaj
•sIsivrD a-auptus pur, suid.mold se sa.Trqna�x gos 4u-afWrj4
qatis ao a2vdaas (rmaqq si saj.rtujj%a aqj ut pataple
-110D 40, -PaILU'll'?s St 110s a41 t[WIM. 4UDLUaAOtU,. XO4LA,,L
jr,D14.19A ZOJ a Saj,-MtjSa aU.1 'j!OS 0141 UT X-01MAN TO 411-9lu
-;w&om pnwumop a-qA a-maal.),ut !req4 lainlral jo uOrl'op
-ua2 pue I-Ellwaod loatilmu4s gos Alsafrunlaud 'Vlp4 aiij,
ur paA.tasqo sat Isn'larnmr, tip aos a4l 2uoune sdill4guoljul
-4j u iou I. o stsvq aq uo pal-awl
st.
'Sgos
jvir%,-,qs pup aeaqjaoj ti-ep �5a4 uo par sa-,OtjVAJ-agqo plat;
uo pasvq wr salt wilsa aqj -I!os tlava yo uGpd 1"Pid4
sail ul 1pa4rDrput. Njdap ai4j Iv Itiozi.aoti. aofVEu tjo-ea ao�T
UaAl2 aX'g SaaUtUfjVa a$_4UL IMS13 SUtlaOUISMD Ul 9110S
10 OjARjj_
aq
jaayv 4vqj z)z-allau pu-e Satinaaniuvq.)
L i!.os reja&as aol, sanjuii paivull4sa smkoqe it atq-el
say.tede.id pww.Pqzo Ima) loapkV4
."n
It juoj axnj.7.oru =uill,do oq4 Ajajvui:,xoxddv jz sl
11 Itz-qm: Aql.suap Sap turluamm zrqj luoqg of pal;md=3
.1do 'atria v se ao;
luoT -a
qaralsuo-) uT juu4aodw.t,. axe qup 4im�p- T.nj%.pjjLr
,,.&+!su.ap wricumna pataaaq st Isal uoq-,),edmoD
a% uq pauTrlqp 4:ii;uSp vallim alh ivaluw eam.st otu
ut aaaaxaut qllj& samz.)ap 41suop aql juvg ia�N
--patrnmx sr1maluoo a.mlstoul tanwildo aqj 11, lan Sasilala
P
-all 4ua�u6z) axn,4 qotu atil -4aaj.663 anristow awAStIq
Lja.&tsmans 'Ll It, am-ij, qa�n 'j,,tolp ia.,vq3vadiaiazi juv1su'6
r q' lm, m, Saum puoAas PaIncituo"3 sl jumalem [!OS n44 jo
uldmvs -e 'Isal uop;ndum to aqll Ul
xapul _kj!;)jj%rjd
put, I.tLu!T ptnbrl 'SaSSIBum, 1v')ruvq3aul I.,4puap unjscotu
-1+!trn. 2lulddra ajoiqtA aq ;* 4oj�w_qaq
us y dtuoia atn zol. uo,- Sat vtu aaS V . a mu f,! I n 2wddlilu Silu,
gdigavap pur d.41 'dos p spuq 4ulaupwp axotu zo o,&q jo dn P-r ru
I-t'
z7v
--------------
. I 1 11113 Sumol �
------------- Paw 41ITN' Om
KS, ------------
T-V CYIS 'JO
1-Y I '11,001-af)
T-V as 'ao
90
L ftwaulouj— 6 salay.1
-41
ann,%-Di t crsfj I qldaa.
yalkUas TLOS
---_.-------- - -951. il ,
----- «-- - - - - -- Illd
Ind doxnno gown
p
01
:S4.uaq!jO!u9L
__. --------- -------- _g dS
joqwS.-. dy;w
Pav 3;tum
(Jos
:vqOquS
OL
Ala!A 'purs Xlqqm hn,& 1-mr, Suals; AA;1A,
09--?l
--------------------- �__,_PuusSuals
CI-0
-PU�35 AIJOA1,12
,fJaA 'PVC8 AL OD Sil-A 'Puu- SuOls S-aA
09--91
------- punce klqqo,,)
el-()
-41
ann,%-Di t crsfj I qldaa.
yalkUas TLOS
---_.-------- - -951. il ,
----- «-- - - - - -- Illd
Ind doxnno gown
p
01
:S4.uaq!jO!u9L
__. --------- -------- _g dS
joqwS.-. dy;w
Pav 3;tum
(Jos
:vqOquS
OL
II RIVERSIDE COUNITY, CALIFORNIA 71
I �vn4 class•ficatimis—Continued
Fra ta
sieve �LIFMCI'_OD
!L-nit
i0del
T 40
PCs
20-30
645-80
60-75
25-40
�540
NP
NTP
20-4.5
4€}-W
30-M)
152_5
0-5
----------------------
M-30
40-60
115-40
210-30
1-111
------------------
INP
20-45
40-60
0_5
N?
0
90-100
75-100
65-95
2",
20-35
0-10
I -- ---------------
NT
' 0
70-90
94-100
50-75
75-400
8590
30-50
- ----------------
N?
1_
� I
tO114 mots t Ure content also influence the swelliag of
oils, Sh-tinking and swelling of some soils can cause
damage to au.;]Aing foundations, basement walls, roads,
and other structures unless special designs are used.
'high shrink,swell potential, indjeates that special
�es and added expense may be required* U 'the
planned use of the soil will not tolerate large volume
IP'$k of corrosion pertnins to -potential soil-induced
chemical action that dissolves or weake'ns uncoated
steel or concrete. Tice rate of corrosion of 'uncoated
steel is related to soil moisture, paxUcle-size distribu-
'tion, total acidity, and electrical conductivity of the
soil material.. The -rate of corrosion of concrete is
based .mainly on the sulfate content, textiriv, and acid-
ity of the soil. Protetqive measares for steel or more
Iresistant concrete help to *avoid, or mini'mize damave
resulting from the corrosion. 'Uncoated steel inter-
setting soil boundaries or soil horizons is were sus-
ceptible to corrosion than an installation that is
1entirely within one kind of soil or NvAltin one soil
horizon.
Evrasiaa factors are used to p:redict the exodibillity
of a soil and its tolerance to erosion in relation to
'specific Id-nds of land use and treatment. The soil
erodibili°ty factor (K) is a raeasure of the susceptibility
of the so.11 to erosion. by water. Soils having the highest
K values are the most erodible. K values ravage htom
I0.10 to 0.64. To estimate armual soil loss per acre. the
K value of a soil is -modified by factors representing
plant cover, grade and leagth of slope, management
practices, and climate, The soil-loss tolerance factor
(T) is 4he maximum rate of so!] erosion, whether
I
from. rainfall or soil blowing., that can occur without
reducing crop production. or environmental quality.
u
� I
The rate is expressed in torts of soil loss per acre per
year.
Wiad erodibiUty groups are made up of soils that
hiave similar properties that affect their resistance to
soil blomiing tf culti-vated. The groups are used to
predict the susceptibility of soil to blowing and the
amount of soil lost- as a result of blowing. Soils are
p,ouped accor6ing to the follwi&ring distinetions:
Sands, Coarse sands, fine sands, and very fine sands,
These soils are e-.-cLremely erodible, so vegetation is
difficult to establish. They are generally not suitable
for crops.
Iaoaray sands, loamy, qne sands, and loamy very fine
sands. These soils are very highly erodible, but crops
can be grovrn if intensive ine-asures to control soil
blo%& ing are used-
Sandy loamy, coarse sandy loamy, fine sandy loams,
and very -fine sandy loarns. These soils are highly erod-
:ible, but crops can be grown.if intensive measures to
control soil blowing are used.
Calcareous loamy -soils that are less than 35 percent
cLiy and more than 5 percent finely divided calcium
carbonate. These soils are erodible., but crops can be
grown if intaitsive naeasures to control soil blowing
are used.
Clays, silty clays, clay foams; and silty clay loams
that are more than 35 percent' clay. These soils are
moderately erodible, but crops can be -,roNrn if mea-
sures to Coatrol soil blowing are used.
Loamy soils that are less than IS percent clay and
less than 5 percent finely divided calcium carbonate
and sandy clay loarns and sandy clays that are less
than 6 percent finely divided calcitun carbonate. These
soils are slic,,,htty erodible. but crops can be grown if
meazures to control soil blowbig are used.
Loamy soils thaat- are 18 to 35 percent clay and less
Reference: USGS Topographic Map
La Quinta, CA Quadrangle
Scale 1:25,000
Site Coordinates
Lat: 33.612N
Long: 116.251W
LANDMARK
Plate
Project No.: LP05046 Topographic Map A-4
r
...F.w....errx..wmc.�:.aw�rs.
i
s.�,zmo�.rv.5... ...
"_ . ..�.- ,e: . . ..,w,t...ewwr..a=
...ce <•
-8
�_,
{�+
s
FI
h
i
1
•••
�
• x13'#11
�
.t
•z Jam.-'",?— ... >.w.wr..•c
.t VENUE E
° .. Se
..v,:.s.�Grv'�. vrw.. i.
wwr.sw•.,:m.a ->
28
a
Project
Site .i�
jiIc
,^= v FIJI:
!E.l. %
� � .:.Y RSi:L�£L'C`
ry,..f
�• n 'x •32f•'
.... ........ ^_a'
�... �.�,,+„• +a
.su.ii.. aY_-
� ». _... .. .Pl;- xwis!?Ya°,e..
,
1
i
/'
G
Iw
{.
�, r11F
It
r
. v _w M.
�, ,...,,
•r..a.=q .... "��
� � . w.yresxne.
w+n+- ...rc. _
AVE
it
1 •
If
�
$kvnm,:nq Ryan
"r•
{
j
33
j {4 {
Reference: USGS Topographic Map
La Quinta, CA Quadrangle
Scale 1:25,000
Site Coordinates
Lat: 33.612N
Long: 116.251W
LANDMARK
Plate
Project No.: LP05046 Topographic Map A-4
Working Group on California Earthquake Probabilities (WGCEP), 1992, Future seismic
hazards in southern California, Phase I Report: California Division.of Mines and
Geology.
Working Group on California Earthquake Probabilities (WGCEP), 1995, Seismic hazards
in southern California, Probable Earthquakes, 1994 -2014, Phase II Report:
Southern California Earthquake Center.,
Youd, T. Leslie and Gams, C. T., 1995, Liquefaction induced ground surface disruption:
ASCE Geotechnical Journal, Vol. 121, No. 11.
Naeim, F. and Anderson, J. C., 1993, Classification and evaluation of earthquake records
for design: Earthquake Engineering Research Institute, NEHRP Report.
National Research Council, Committee of Earthquake Engineering, 1985, Liquefaction of
Soils during Earthquakes: National Academy Press, Washington, D.C.
Porcella, R. L., Matthiesen, R: B., and Maley, R. P., 1982, Strong - motion data recorded
in the United States: U.S. Geological Survey Professional Paper 1254, p. 289-
318.
Robertson, P. K., 1996, Soil Liquefaction and its evaluation based on SPT and CPT: in
unpublished paper presented at 1996 NCEER Liquefaction Workshop
Seed, Harry B., Idriss, I. M., and Arango I., 1983, Evaluation of liquefaction potential
using field performance data: ASCE Geotechnical Journal, Vol. 109, No. 3.
Seed, Harry B., et al, 1985, Influence of SPT Procedures in Soil Liquefaction Resistance
Evaluations: ASCE Geotechnical Journal, Vol. 113, No. 8.
Sharp, R. V., 1989, Personal communication, USGS; Menlo Park, CA.
Stringer, S. L., 1996, EQFAULT.WK4, A computer .program for the estimation of
deterministic site acceleration.
Stringer; S. L. 1996, LIQUEFY.WK4, A computer program for the Empirical Prediction
of Earthquake - Induced Liquefaction Potential.
Structural Engineers Association of California (SEAOC), 1990, Recommended lateral
force requirements and commentary.
Tokimatsu, K. and Seed H. B., 1987, Evaluation of settlements in sands due to
earthquake shaking: ASCE Geotechnical Journal, v. 113, no. 8.
U.S. Geological Survey (USGS), 1990, The San Andreas Fault System, California,
Professional Paper 1515.
U.S. Geological Survey {USGS), 1996, National Seismic Hazard Maps: available at
http://gldage.cr.usgs.gov
Wallace, R. E., 1990,. The San Andreas Fault System, California: U.S. Geological
Survey Professional Paper 1515, 283 p.
Working Group on California Earthquake Probabilities (WGCEP), 1988, Probabilities of
large earthquakes occurring in California on the San Andreas Fault: U.S.
Geological Survey Open -File Report 88 -398.
REFERENCES
Arango I., 1996, Magnitude Scaling Factors for Soil Liquefaction Evaluations: ASCE
Geotechnical Journal, Vol. 122, No. 11.
Bartlett; Steven F. and Youd, T. Leslie, 1995, Empirical Prediction of Liquefaction -
Induced Lateral Spread: ASCE Geotechnical Journal, Vol. 121, No. 4.
Blake, T. F., 1989 -1996, FRISKSP A computer program for the probabilistic estimation
of seismic hazard using faults as earthquake sources.
Bolt, B. A., 1974, Duration of Strong Motion: Proceedings 5th World Conference on
Earthquake Engineering, Rome, Italy, June 1974.
Boore, D. M., Joyner, W. B., and Fumal, T. E., 1994, Estimation of response spectra and
peak accelerations from western North American earthquakes: U.S. Geological
Survey Open File Reports 94 -127 and 93 -509.
Building Seismic Safety Council (B.SSC), 1991, NEHRP recommended provisions for the
development of seismic regulations of new buildings, Parts 1, 2 and Maps:
FEMA 222, January 1992
California Division of Mines and Geology (CDMG), 1996, California Fault Parameters:
available at http: / /Www.consrv.ca.gov /dmg/shezp /fltindex.html.
Ellsworth, W. L., 1990, Earthquake History, 1769 -1989 in: The San Andreas Fault
System, California: U.S. Geological Survey Professional Paper 1515, 283 p.
International Conference of Building Officials (ICBO), 1994, Uniform Building Code,
1994 Edition.
International Conference of Building Officials (ICBO), 1997, Uniform Building Code,
1997 Edition.
Jennings, C. W., 1994, Fault activity map of California and Adjacent Areas: California
Division of Mines and Geology, DMG Geologic Map No. 6.
Jones, L. and Hauksson, E., 1994, Review of potential earthquake sources in Southern
California: Applied Technology Council, Proceedings of ATC 35 -1.
Joyner, W. B. and Boore, D. M., 1988, Measurements, characterization, and prediction of
strong ground motion: ASCE Geotechnical Special Pub. No. 20.
Mualchin, L. and Jones, A. L., 1992, Peak acceleration from maximum credible
earthquakes -in California (Rock and Stiff Soil Sites): California Division of
Mines and Geology, DMG Open File Report 92 -01.
SUMMARY OF INFILTRATION TESTING
Client: RT. Hughes Co, LLC.
Project: Proposed Coral Mountain Estates
Job No.: LP05098
Date: 05/24/05
Test Hole No.: 1 -2
Date Excavated: 04/22/05
Technician: 113
Location: See Site and Exploration Plan
Soil Type: Silty Sand (SM)
Total Depth of Test Hole: 3 ft.
Total
Initial
Final
Fall
Reading
Time
Elapsed
Water
Water
in Water
Stabilized
Rate
No.
Time
Interval
Time
Level
Level
Level
Drop
min
min
in.
in.
in.
min /in
al /hr /sft
1
15
15
0.00
2.75
2.75
2
15
30
0.00
2.75
2.75
3
15
45
0.00
2.50
2.50
4
15
60
0.00
2.50
2.50
5
30
90
0.00
5.00
5.00
6
30
120
.0.00
5.25
5.25
7
60
180
0.00
8.00
8.00
8
60
240
0.00
8.00
8.00
9
60
300
0.00
8.50
8.50
10
60
360
0.00
8.00
8.00
7.38
5.07
SUMMARY OF INFILTRATION TESTING
Client: RT. Hughes Co, LLC.
Project: Proposed Coral Mountain Estates
Job No.: LP05098
Date: 05/24/05
Test Hole No.: 1 -1
Date Excavated: 04/22/05
Technician: JB
Location: See Site and Exploration Plan
Soil Type: Silty Sand (SM)
Total Depth of Test Hole: 3 ft.
Total
Initial
Final
Fall
Reading
Time
Elapsed
Water
Water
in Water
Stabilized
Rate
No.
Time
Interval
Time
Level
Level
Level
Drop
min
min
in.
in.
in.
min /in
al /hr /sft
1
15
15
0.00
1.00
1.00
2
15
30
0.00
1.50
1.50
3
15
45
0.00
1.00
1.00
4
15
60
0.00
1.50
1.50
5
30
90
0.00
3.00
3.00
6
30
120
0.00
3.50
3.50
7
60
180
0.00
5.00
5.00
8
60
240
0.00
4.75
4.75
9
60
300
0.00
4.75
4.75
10
360
0.00
4.75
4.75
12.47
3.00
60
LANDMARK CONSULTANTS, INC.
CLIENT: RT Hughes Co, LLC
PROJECT: Coral Mountain Estates, La Quinta, CA
JOB NO: LP05098
DATE: 05/26/05
CHEMICAL ANALYSES
Boring:
B -2
CalTrans
Sample Depth, ft:
0 -5
Method
pH:
6.82
643
Resistivity (ohm -cm):
1,500
643
Chloride (Cl), ppm:
260
422
Sulfate (SO4), ppm:
212
417
General Guidelines for Soil Corrosivity
Material Chemical
Amount in
Degree of
Affected Agent
Soil (Ppml
Corrosivity
Concrete Soluble
0-1000
Low
Sulfates
1000-2000
Moderate
2000-20000
Severe
> 20000
Very Severe
Normal Soluble
0-200
Low
Grade Chlorides
200-700
Moderate
Steel
700-1500
Severe
> 1500
Very Severe
Normal Resistivity
1 -1000
Very Severe
Grade
1000 -2000
Severe
Steel
2000- 10,000
Moderate
10,000+
Low
LANDMARK
Geo-Engineers and Geologists Selected Chemical Plate
a DBE /MBE /SBE Company
Project No: LP05098 Analyses Results C-4
145
140
135
130
125
WI
OEM
ti
c
m
p 120
115
110
105
100
............ _ ...._........ ........... .... ..............................
Client
RT Hughes Co. LLC
.............. ............_.....,.. ... ........
I Project: Proposed
Coral Mountain Estates
- - - .._.!_.._... _..... _..,..... ..._ . ........ .....
Project act No'
_. _. _...._._......._...... .... ... . _. . .. .. ......
Date:
05/25/05
. _ ..... ........ ............ ....... .... :............. ........ :......
I
SUMMARY OF TEST RESULTS
.... ...... ._ _.._.__
i Description:
Silty Sand (SM)
Sample Location-
B-1 @ 0 5 ft
T est Method:
ASTM D1557A
Maximum Dry
_..._ ...._c.._.... ........_.......;._ .........._ . ........................:...... .�
Density (pc
121 5
! pfi
O mum Moisture
Content ( %):
10.5
Curves of 100%
saturation for
specific gravity
equal to:
2.75
— 2.70
2.65
0 5 10 15 20 25 30
Moisture Content ( %)
Leo-Engineers AND MARK and Geologists Plate
a DBE/MBEISBE Company
Project No: LP05098 Moisture Density Relationship C -3
2
1
0
-1
-2
-3
L
-4
_ -5
C
rn
c -6
m
L
U
c -7
U
N
CL -8
-9
-10
-11
-12
-13
-14
COLLAPSE POTENTIAL TEST (ASTM D5333)
0.1 1 10 100
Pressure(kso
Results of Test: Initial Final
Dry Density, pcf: 92.9 99.2
Water Content, %: 1.8 25.3
Void Ratio, e: 0.782 0.670
Saturation, %: 6 100
Leo-E AND MARK
Gngineers and Geologists
e UBE/MBEISSE Company
Project No: LP05098
Collapse Potential
Test Results
Plate
C -2
SIEVE ANALYSIS
HYDROMETER ANALYSIS
Gravel
Sand
Silt and Clay Fraction
Coarse Fine
Coarse Medium Fine
IN I
�I
off
MGeo-Engineers
and TGeologisls
Project No.: LP05098
Grain Size Analysis
SIEVE ANALYSIS
HYDROMETER ANALYSIS
Gravel
Sand
Silt and Clay Fraction
Coarse Fine
Coarse Medium Fine
PRIMARY DIVISIONS
Gravels Clean
More than half gravels (less than
of 5 %fines
coarse fraction
Coarse grained soils is Gravel
larger than No. with fines
More than half of 1 4 sieve
material is larger Sands Clean sands (less
than 5 %fines)
than No. 200 sieve More than half
of coarse
fraction and
is smaller than with fines
Silts and clays
Fine grained soils Liquid limit is
less than 50%
More than half of
material is smaller Silts and clays
than No. 200 sieve Liquid limit is
more than 50%
Highly organic soils
Silts and Clays
Fine
GW I Well graded gravels, gravel -sand mixtures, little or no fines
GP Poorly graded gravels, or gravel -sand mixtures, little or no fines
GM Silty gravels, gravel- sand -silt mixtures, non - plastic fines
GC Clayey gravels, gravel- sand -clay mixtures, plastic fines
SW Well graded sands, gravelly sands, little or no fines
SP Poorly graded sands or gravelly sands, little or no fines
SM Silty sands, sand -silt mixtures, non - plastic fines
SCII Clayey sands, sand -clay mixtures, plastic fines
ML Inorganic silts, clayey silts with slight plasticity
CL I Inorganic clays of low to medium plasticity, gravely, sandy, or lean clays
I: ;I:
OL
Organic silts and organic clays of low plasticity
I I
I II MH
Inorganic silts, micaceous or diatomaceous silty soils, elastic silts
J 01 CH I Inorganic clays of high plasticity, fat clays
EOH Organic clays of medium to high plasticity, organic silts
PT Peat and other highly organic soils
GRAIN SIZES
Sand Grave Cobbles Boulders
Medium Coarse Fine Coarse
200 4 10 4
US Standard Series Sieve
Sands Gravels etc.
Blows/ft. '
Very Loose
0-4
Loose
4 -10
Medium Dense
10 -30
Dense
30 -50
Very Dense
Over 50
3/4" 3" 12"
Clear Square Openings
Clays & Plastic Silts
Strength
Very Soft
0 -0.25
0 -2
Soft
0.25 -0.5
2-4
Firm
0.5 -1.0
4 -8
Stiff
1.0 -2.0
8 -16
Very Stiff
2.0 -4.0
16 -32
Hard
Over 4.0
Over 32
Number of blows of 140 lb. hammer falling 30 inches to drive a 2 inch 0. D. (1 3/8 in. 1. D.) split spoon (ASTM 01586).
Unconfined compressive strength in tons /s.f. as determined by laboratory testing or approximated by the Standard
Penetration Test (ASTM D1586), Pocket Penetrometer, Torvane, or visual observation.
Type of Samples:
11 Ring Sample N Standard Penetration Test I Shelby Tube 0 Bulk (Bag) Sample
Drilling Notes:
1. Sampling and Blow Counts
Ring Sampler - Number of blows per foot of a 140 lb. hammer falling 30 inches.
Standard Penetration Test - Number of blows per foot.
Shelby Tube - Three (3) inch nominal diameter tube hydraulically pushed.
2. P. P. = Pocket Penetrometer (tons /s.f.).
3. NR =No recovery.
4. GWT= = Ground Water Table observed @ specified time.
LANDMARK
o�M-- . Geologists
�S� Co-p- Plate
Project No: LP05098 Key to Logs B-4
0
O C71
O CTl O Ul O
DEPTH
r
n
O
r
-03.
CLASSIFICATION
�
0
m
z
: ::
0
SAMPLE TYPE
z
�
0 rq�
to
Ln 00 v
W
BLOWS /FOOT"
o
• •
POCKET PEN. (TSF)
N
CQ
a
='
�.
z m
U)
p
a
o
o
N
0
C -
°
a
m
O
-n m
x
°
O
n (O
r
>
3 co
(n
m 7
°
°
r
n
>
°
o
a
'
C
D
z
m
;o
m
N n
-
p� �p
�
m
<
m
o'
>
�'
5'
m°
mW
m
�;
N
vm
a 0
m Q,
=
— m
a)
CD 0
7=
a
O
Z -n
m
1 °
CD
CD
CL
a
D
o�
3
0O 00
:3_'
a
T
\
y.
C
CD
Z
^
0
g>
3-
>
CD
0
D
O
.
=r
�'
-i
o
I.■�I
m
•
3 m
°
w
o
3
;o
N3
D
r
m
z
P
0
-�
MOISTURE
D
-+
N
CONTENT( %)
r
f l
m
G)
0
DRY UNIT WT. (PCF)
rN
co
w
co
M
m
c
UNCONFINED
W
G
°
COMPRES310N (T3F)
0
IT
LIQUID LIMIT
co
A
CD
N
1
�
N
W Q)
PLASTICITY INDEX
O
W
Cn
PASSING #200
O
V1 O U1 O (.n O
DEPTH
0
"1]
n
O
j-
CLASSIFICATION
m
n
Q
SAMPLE TYPE
Z
z
cn
r*
(
co Z
W v
BLOWS /FOOT-
"•
CD
1
0
POCKET PEN. (TSF)
cn
(D
Q
=r
N.
z
p
7
aon
n
cn
°cn�
-i
p
o
O
�o
a
cn
��D
C
x
�.�
>>
°
jo
c
3
<
m
(nm
C7
o
o
lr-
(�
m o
C �.
�
a
CD
-
z
X. O
-
o
:3
�
m
U)) o
or
v to
m 0)
U)
CD
CL
- _
:3
m a
0o
O m 0
a,
(D-�
0
cam
o
Z -
• I�
CD
a
o
CD
°
p
g
o�
c
3
p
n o 0
OJ a
=
N
a >
j
Z
n
•
3-a
Q
D
a
°' y
T
D
O
o
�CA
CD
m
o
•�
.�
3 D
a
Q
3
°
CD
D
m
z
O
MOISTURE
0
D
?r
CONTENT( %)
r
m
m
G)
O
C(»
DRY UNIT WT. (PCF)
co
o
m
5
_
R -Value
co
<
M
°
..
3
c:)
Sand Equivalent
co
(3D
W �
N
Q)
PLASTICITY INDEX
O
N �
�
PASSING #200
4
CLIENT: RT. Hughes Co., LLC METHOD OF DRILLING: CME 55 vdautohammer
PROJECT: Proposed Coral Mountain Estates - La Quinta, CA DATE OBSERVED: 04/22/05
LOCATION: See Site and Exploration Plan LOGGED BY: TB
LOG OF BORING B -1
o
W
o
¢
a
o
O
z
SHEET 1 OF 1
se
Z
°
Z y
it
o
N
LU
N
a
3
a
Y
DESCRIPTION OF MATERIAL
W
~
y W
Z
Z I
LL W CL
o
F
3
Z
IL
o
v
U
m
a
SURFACE ELEV. +/-
2
U
LL
Y U
o a
U 2
v
:
y
g
In
a
YA
SILTY SAND (SM): Brown, humid, fine grained.
23
5
15
medium dense
1.8
92.9
10
17
SANDY SILT (ML): Brown, medium dense, damp.
3.2
90.4
-15-
TT
24
SILTY SAND /SANDY SILT (SM /ML): Brown, medium
1.0
982
dense, humid, fine grained.
20-
19
25
:.
17
30
17
SANDY SILT (ML): Olive brown, medium dense, damp.
35-
24
SILTY SAND (SM): Brown, medium dense, damp,
fine grained.
40
'
22
45-
32
SANDY SILT (ML): Brown, dense, moist.
50
34
SILTY SAND (SM): Brown, dense, moist, fine grained.
End of Boring at 51.5 ft
55
No Groundwater Encountered
•* Blows not corrected for overburden pressure, sampler
size or increase drive energy for automatic hammers.
Project No:
LANDMARK
Plate
LP05098
-• -- • -.00
B -1
a DOE MBE/SBE Compai V
F