Loading...
BRES2018-0301 Soil and Foundation Evaluation Reportsail P CIFIC INC. Geotech nicA a nJ EnvironmentA Services Mr. Prasad 78155 Calle Cadiz La Qunita, California CITY OF LA QUANTA BUILDING DIVISION REVIEWED FOR CODE COMPLIANCE DATdah1I_Zg1rB Subject: Soil and Foundation Evaluation Report Proposed Single Family Building APN 770-156-006 Calle Cadiz, La Quinta, California Dear Sir; Project No. A-6841-19 February 14, 2019 Q L a \ o= _ o z N _/ L � a Z! s a �o d i yQf Q U p Q W Pursuant to your authorization, we are pleased to submit our report for the subject project. Our evaluation was conducted in February 2019. This evaluation consists of field exploration; sub- surface excavation, logging, and soil sampling; laboratory testing; engineering evaluation and preparation of the following report containing a summary of our conclusions and recommendations. The opportunity to be of service is appreciated. Should any questions arise pertaining to any portion of this report, please contact this firm in writing for further clarification. Very truly, Soil Pacific Inc. Dr. Yones Kabir Foss Eftekhari President RCE RECEIVED w EsGil A SAFEbulft Company DeRpFESSlo 1, EF7Ek'yE� M 0 r7 CM r � c No. C50121 r FXP._44. 10 �/1 stq� cfw_ FOF CALF 675 N. lEckhoff, Suite A, Orange, CA 92868 Orel (714) 879-1203 Wax (714) 879-4812 Soil and Foundation Evaluation Report Proposed Single Family Building APN 770-156-006 Calle Cadiz, La Quinta, California Prepared For: Mr. Prasad 78155 Calle Cadiz La Qunita, California Prepared by: SOIL PACIFIC INC. 675 N. ECKHOFF STREET, SUITE A ORANGE, CALIFORNIA 92868 Tel. (714) 879 1203 Project No. A-6841-19 February 14, 2019 Introduction 1.1 Description of Site 1.2 Planned land Use 1.3 Field Exploration 1.4 Laboratory Testing 1.4.1 Classification 1.4.2 Expansion Potential 1.4.3 Direct Shear 2.1 Earth Materials 2.2 Foundations 2.3 Bearing Materials 2.4 Groundwater 2.5 CBC Seismic Design Parameters 2.6 Chemical Contents 2.7 Liquefaction Table of Contents Section 1.0 Preliminary Soils Evaluation Section 2.0 Conclusions Section 3.0 Recommendations 3.1 Clearing and site preparation 3.2 Site Preparation and Excavation 3.3 Stability of Temporary Cuts 3.4 Foundations 3.4.1 Bearing Value 3.4.2 Isolated Pad Footing 3.4.3 Foundation Settlement 3.4.4 Concrete Type 3.4.5 Slab on grade 3.4.6 Pile Foundation 3.5 Utility Trenches Backfill 3.6 Seismic Design and Construction 3.7 Surface and Subsurface Drainage Provisions 3.8 Conventional Retaining Wall 3.9 Concrete Driveway 3.10 Storm Water Management 3.11 Observation and Testing Illustrations Appendix A Field Exploration Appendix B Laboratory Testing Appendix C References Appendix D General Earthwork & Grading Specifications Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California Soil and Foundation Evaluation Report Proposed Single Family Building APN 770-156-006 Calle Cadiz, La Quinta, California LIMITATIONS Page: 4 Between exploratory excavations and/or field testing locations, all subsurface deposits, consequent of their anisotropic and heterogeneous characteristics, can and will vary in many important geotechnical properties. The results presented herein are based on the information in part furnished by others and as generated by this firm, and represent our best interpretation of that data benefiting from a combination of our earthwork related construction experience, as well as our overall geotechnical knowledge. Hence, the conclusions and recommendations expressed herein are our professional opinions about pertinent project geotechnical parameters which influence the understood site use; therefore, no other warranty is offered or implied. All the findings are subject to field modification as more subsurface exposures become available for evaluations. Before providing bids, contractors shall make thorough explorations and findings. Soil Pacific Inc., is not responsible for any financial gains or losses accrued by persons/firms or third party from this project. In the event the contents of this report are not clearly understood, due in part to the usage of technical terms or wording, please contact the undersigned in writing for clarification. Project No. A-6841-19 Page: 5 APN 770-156-006 Calle Cadiz, La Quinta, California SECTION 1.0 PRELIMINARY EVALUATION 1.1 Site Description The area covered by our investigation consists of a vacant and undeveloped parcel of land located within residential zoned of LaQuinta community at south east of the City of Palm Desert and 4 miles south of 10 freeway. The property is rectangular parcel identified as APN 770-156-006. The item property is flat in general with an average elevation of 40 feet above main sea level. Surrounding properties are single family residences at the north, and east sides. Southern property boundary is limited to a commercial development. Site access is through Calle Cadiz at the north. Site sheet flow is generally toward the north, northeast. 1.2 Planned Land Use It is understood that the proposed construction will consist of construction of a newly designed single family residential building. 1.3 Field Exploration Subsurface conditions were explored by an auger boring at two locations to a minimum explored depth of 12-16 feet below the existing grade. Underlying materials consist of mainly sandy soils with some silt interbedded with sand and scattered gravel. The exploratory borings were classified and logged by the field engineer in accordance with the visual -manual procedures of the Unified Soil Classification System (USCS), ASTM Test Standard D2488. Following our exploration, borings were loosely backfilled with the soil cuttings. The approximate locations of the exploratory borings are shown on the Exploration Location Map Figure A-1-1. Descriptive boring logs are presented in Appendix A. 1.4 Laboratory Testing 1.4.1. Classification Soils were classified visually according to the Unified Soil Classification System. Moisture content and dry density determinations were made for the samples taken at various depths in the exploratory excavations. Results of moisture -density and dry -density determinations, together with classifications, are shown on the boring logs, Appendix A. 1.4.2 Expansion An expansion index test was performed on a representative sample in accordance with the California Building Code Standard. Soil expansion potential for the site is not anticipated. Soil expansion for the site is EI=0. 1.4.3 Direct Shear Shear strength parameters are determined by means of strain -controlled, double plain, direct shear tests performed in general accordance with ASTM D-3080. Generally, three or more specimens are tested, each under a different normal load, to determine the effects upon shear resistance and displacement, and strength properties such as Mohr strength envelopes. The direct Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California Page: 6 shear test is suited to the relatively rapid determination of consolidated drained strength properties because the drainage paths through the test specimen are short, thereby allowing excess pore pressure to be dissipated more rapidly than with other drained stress tests. The rate of deformation is determined from the time required for the specimen to achieve fifty percent consolidation at given normal stress. The test can be made on all soil materials and undisturbed, remolded or compacted materials. There is, however, a limitation on maximum particle size. Sample displacement during testing may range from 10 to 20 percent of the specimen's original diameter or length. The sample's initial void ratio, water content, dry unit weight, the degree of saturation based on the specific gravity, and mass of the total specimen may also be computed. The shear test results are plotted on the attached shear test diagrams and unless otherwise noted on the shear test diagram, all tests are performed on undisturbed, saturated samples. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California _ xw�' 1 _ c L- � i `� s f � r 1 .k mn r� 4.! J Fig. 1:Site aerial photo. Page: 7 � � r s r •� 0 Ell Project No. A-6841-19 Page: 8 APN 770-156-006 Calle Cadiz, La Quinta, California �waty ►'►Eel! • o � r ' } 01 .fee Iwo oft a 1 � ■ s}=:;• , ; La Quinta : • ■ •# `•j�w�• j• r r ■ Figure 2: Site topographic map. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California Section 2.0 Conclusions Page: 9 The proposed construction is considered feasible from a soils engineering standpoint. All earthwork should be performed in accordance with applicable engineering recommendations presented herein or applicable Agency Codes, whichever are the most stringent. 2. 1 Earth Materials Encountered soils at the site consisted of a granular sandy soils. Soil boring logs indicated sandy soils are interbedded with silty sand with scattered gravely sand to the explored depth. On -site soils are dense and damp. 2.2 Foundations All proposed newly design foundation should be placed on approved engineered fill. 2.3 Bearing Materials Surficial soils up to depth of 2feet are exposed to extreme weather and cannot be used as bearing materials. Approved and certified engineered fill will be used as an adequate materials. 2.4 Groundwater The site is located within the Coachella Valley, Indio Groundwater basin (California Department of Water Resources, [CDWR], 2016). Groundwater depth varies within the area and flow direction beneath the subject site is toward the south. Groundwater during our subsurface exploration program was not encountered at a depth of sixteen feet below the existing grade. Groundwater at the site is expected to be deeper than 50 feet. 2.5 CBC Seismic Design Parameters Earthquake loads on earthen structures and buildings are a function of ground acceleration, which may be determined from the site -specific acceleration response spectrum. To provide the design team with the parameters necessary to construct the site -specific acceleration response spectrum for this project, we used computer application that is available on the United States Geological Survey (USGS) website, https://earthquake.usgs.gov/ws/designmaps/ or https://asce7hazardtool.online. Specifically, the Design Maps website https://earthquake.usgs.gov/ws/desigmnaps/asce7-16.html was used to calculate the ground motion parameters. 2008 PSHA Interactive Deaggregation website http://geohazards.usgs.gov/deaggint/2008/ may be used to determine the appropriate earthquake magnitude. Based on our review of pertinent CGS maps, no active or potentially active faults are known to traverse the area of the proposed development at the subject site. However, Southern California is seismically active with numerous faults capable of causing ground shaking at the site. The general location of active and potentially active faults within the southern California region can generate ground shaking at the site. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California 2.6 Chemical Contents Page: 10 Chemical testing for detection of hydrocarbon or other potential contamination is beyond the scope of this report. 2.7 Liquefaction Study/ Secondary Seismic Hazard Zonation Based on our the Liquefaction open file report of County of Riverside the potential for liquefaction at the subject site is low. Liquefaction occurs when seismically -induced dynamic loading of a saturated sand or silt causes pore water pressures to increase to levels where grain -to -grain contact pressure is significantly decreased and the soil material temporarily behaves as a viscous fluid. Liquefaction can cause settlement of the ground surface, settlement and tilting of engineered structures, flotation ofbuoyant buried structures and fissuring of the ground surface. A common manifestation of liquefaction is the formation of sand boils (short-lived fountains of soil and water emerges from fissures or vents and leave freshly deposited conical mounds of sand or silt on the ground surface). Lateral spreading can also occur when liquefaction occurs adjacent to a free face such as a slope or stream embankment. The types of seismically induced flooding that may be considered as potential hazards to a particular site normally includes flooding due to a tsunami (seismic sea wave), a seiche, or failure of a major reservoir or other water retention structure upstream of the site. Since the site has an average elevation of approximately 40 feet above sea level, and since it does not lie in close proximity to an enclosed body of water, the probability of flooding from a tsunami or seiche is considered to be low. In addition, the site is not located within a designated tsunami inundation area. Project No. A-6841-19 Page: 11 APN 770-156-006 Calle Cadiz, La Quinta, California Section 3.0 Recommendations Based on our exploration and experience with similar projects, the proposed construction is considered feasible from a soils engineering standpoint providing the following recommendations are made a part of the plans and are implemented during construction. 3.1 Clearing and Site Preparation Based on review of the proposed project prospect, a newly designed single family building is proposed. Any fill soil, or construction debris if there is any should be removed and hauled away from the site. 3.2 Site Preparation and Excavations If any unanticipated subsurface (pipe lines, irrigation lines, etc.) condition are encountered during earthwork construction, then this office should be informed to provide an appropriate remedial recommendation. 3.3 Soil Removal and Recompaction Site grading plan was not available for review and comment. Site grading will be limited to site preparation and excavation or remove and recompaction (R&R) to approximate depth of 3.0 feet below the existing grade. The following recommendation should be used in preparation of grading plan. 1. The areas to receive compacted fill should be stripped of all vegetation, concrete and pavement debris if there is any, non engineered fill, left in place old foundation concrete and incompetent material up to approved soils. 2. The exposed grade at the building pad area should then be overexcavated to approved earth materials. The excavated area should be scarified to a minimum of 8 inches, adjusted to optimum moisture content, and reworked to achieve a minimum of 90 percent relative compaction. 3. Compacted fill should have a minimum of 1.5 feet depth below proposed footing and extend at least 5 feet beyond all perimeter footings or to a distance equal to the depth of the certified compacted fill, whichever is the greatest and if applicable. Any excavation along the existing building should be slot cut. 4. Compacted fill, consisting of on -site soil shall be placed in lifts not exceeding 6 inches in uncompacted thickness. The excavated onsite materials are considered satisfactory for reuse in the fill if the moisture content is near optimum. Any imported fill should be observed, tested, and approved by the soils engineer prior to use as fill. Rocks larger than 6 inches in diameter should not be used in the fill. 5. The fill should be compacted to at least 90 percent of the maximum dry density for the material. The maximum density should be determined by ASTM Test Designation D 1557-00. Project No. A-6841-19 Page: 12 APN 770-156-006 Calle Cadiz, La Quinta, California 6. Field observation, and compaction testing should be performed by a representative of Soil Pacific Inc. during the grading to assist the contractor in obtaining the required degree of compaction and the proper moisture content. Where compaction is less than required, additional compaction effort should be made with adjustment of the moisture content, as necessary, until a minimum of 90 percent relative compaction is obtained. 7. The excavations are anticipated to be up to 3.0 feet in vertical height including the depth of the exterior wall footing. The excavations are expected to expose fill soils. Excavations in a surcharged area such as being adjacent to an existing structure building/ public road should be slot cut and backfiiled. The slot cutting method employs the earth as a buttress and allows the earth excavation to proceed in phases. Alternate "A", "B" and "C" slots of 8 feet will worked. The slot cut should be completed and backfilled in the "A" slot before the "B" or "C" slot are excavated. All excavations should be stabilized within 30 days of initial excavation. Water should not be allowed to pond on top of the excavation nor to flow towards it. A representative from our office should be present during the process of slot cutting and/or compaction. 3.4 Stability of Temporary Cuts The stability of temporary cut is required during removal process. The stability depends on many factors, including the slope angle, closeness of the adjacent building foundation or public property traffic, the shearing strength of the underlying materials, and the height of the cut and the length of time the excavation remains open and exposed to equipment vibrations and rainfall. The geotechnical consultant should be present to observe all temporary excavations at the site. The possibility of temporary excavations failing may be minimized by: 1) keeping the time between cutting and filling operations to a minimum; 2) limiting excavation length exposed at any one time; and, 3) shoring prior to cut. 3.5 Foundations Considering the site specific condition, the following recommendations may be used in preparation of the design and construction of the foundation system. 3.5.1 Bearing Value Allowable bearing value is 3000 psf to a maximum of 5000 psf. The bearing value may be increased by 1/3 when considering short duration seismic or wind loads. An allowable frictional resistance of 0.40 may be used for design of concrete foundations poured on approved materials. When frictional and passive resistance are combined to compute the total lateral resistance, no reduction is needed to any of these two components. 3.5.2 Foundation Settlement Based upon anticipated structural loads, the maximum total settlement for the proposed foundation is not expected to exceed 1 inch at design load. Anticipated differential settlement for the site will be about .5 inches. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California 3.5.3 Concrete Type Page: 13 Based on our experience with the similar project within the area it is our recommendation to use only concrete type II. 3.5.4 Slabs -on -grade If slabs -on -grade is designed then it should be a minimum of 5 inches in nominal thickness. Slab areas that are to be carpeted or tiled, or where the intrusion of moisture is objectionable, should be underlain by a moisture barrier consisting of 15-mil Visqueen, properly protected from the puncture by four inches of gravel per Calgreen requirements. The slab should be reinforced by rebars no. 4 at 18 inches on center and shall be tied to the foundation. 3.6 Utility Trench Backfill Utility trenches backfill should be placed in accordance with Appendix D. It is the owners' and contractors' responsibility to inform subcontractors of these requirements and to notify Soil Pacific when backfill placement is to begin. 3.7 Seismic Design and Construction Construction should be in conformance with seismic design parameters of the latest edition of California Building Code ( C.B.C.) Please refer to the following table for related seismic design parameters. SS (0.2 sec) S1 (1.0 sec) Soil Site Class SDS (0.2 sec) SDI (1.0 sec) PGAm Seismic Design Cat 1.5 .6 D 1.2 - .712 III 3.8 Retaining Wall Design Recommendations If a conventional retaining wall less than of 6 feet is proposed, the following design criteria, can be used. Any wall in excess of 6 feet height should include seismic loads. 1) A free standing wall can be designed using the minimum equivalent fluid pressure, for lateral soil loads, of 35 pounds per cubic foot for on -site soils conditions having a level backfill (10:1 or less). /2) An allowable soil bearing pressure of 3000 lbs. per square foot maybe used in design for footings embedded a minimum of 24 inches below the lowest adjacent competent grade. 3) A friction coefficient of 0.3 between concrete and natural or compacted soil and a passive bearing value of 350 lbs. per square foot per foot of depth, up to a maximum of 5000 pounds per square foot at the bottom excavation level may be employed to resist lateral loads. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California 3.9 Concrete Driveway/ Pathway Page: 14 The subgrade soils for all flatwork should be checked to have a minimum moisture content of 2 percentage points above the optimum moisture content to a depth of at least 18 inches. 2. Local irrigation and drainage should be diverted from all flatwork areas. Area drains and swales should be utilized to reduce the amount of subsurface water intrusion beneath the foundation and flatwork areas. 3. The concrete flatwork should have enough cold joints to prevent cracking. Adequate reinforcement considering the expansion potential is required. A minimum of rebar no. 4 placed at 18 inches on center must be used. 4. Surface and shrinkage cracking of the finished slab may be significantly reduced if a low slump and water -cement ratio are maintained during concrete placement. Excessive water added to concrete prior to placement is likely to cause shrinkage cracking. 5. Construction joints and saw cuts should be designed and implemented by the concrete contractor or design engineer based on soil conditions. Maximum joint spacing should not exceed 8 feet in any direction. 6. Patio or driveway subgrade soil should be compacted to a minimum of 90 percent to a depth of 18 inches. All run-off should be gathered in gutters and conducted off -site in a non -erosive manner. Planters located adjacent to footings should be sealed, and leach water intercepted. 3.10 Excavation Calosha requires that any excavation exceeding 4 feet in vertical cut require shoring or 1:1 trim above the 4 feet vertical cut. All temporary excavations shall conform to the requirements of CAL -OSHA (Title 8, Division 1, Subchapter 4, Article 6 "Excavations" Sections 1539 to 1547) as well as all specific worker safety requirements as enforced by the local Building Authority. 3.11 Infiltration Rate On -site soils at shallow depth is favorable for infiltration. Single wall infiltration was performed to verify and measure the site infiltration rate. The infiltration rate design is 10 inches per hour. 3.12 Observation and Testing All grading and earthwork including trench backfill should be performed under the observation and testing of the consulting engineer for proper sub -grade preparation, selection of satisfactory materials, placement and compaction of all structural fill. Sufficient notification prior to stripping and earthwork construction is essential in order that the work will be adequately observed and tested. Prior to initiation of grading, a meeting should be arranged by the developer and should be attended by representatives of the governmental agencies, contractors, consultants and the developer. Construction should be inspected at the following stages by the Geotechnical Consultant. Project No. A-6841-19 APN 770-156-006 Calle Cadiz, La Quinta, California Page: 15 It is recommended that representative of Soil Pacific, Inc. be present to observe and test during the following stages of construction: 0 Site grading to confirm proper removal of unsuitable materials and to observe and test the placement of fill. O Inspection of all foundation excavations prior to placement of steel or concrete. O During the placement of retaining wall subdrain and backfill materials. 0 Inspection of all slab -on -grade areas prior to placement of sand, Visqueen. O After trenches have been properly backfilled and compacted. 0 When any unusual conditions are encountered. APPENDIX A Field Exploration ILO Log of Sub -surface Exploration B-1 Std. Pen Drive USCS Letter Equipment Type: ASM Boring # B-1 Wt: Bulk/Bag Drop: Graphic Diameter: 4" Logged by: A.Sh. Date:2/14/19 Ring Laboratory Depth: 16 feet G.water: - Backfilled:Y MOIstnr Dryer Description of Earth Materials feet N g 5- 10- 15- 20- 25- 30 35- 40- 6.8 4.0 SM Light brown, fine grained silty sand, and sand, damp to moist, top soil. 112.7 1 Sp Light brown, fine to medium grained sand with tarce of silt damp to dry, native. 110.4 . Sp + Light brown to brown suger sand, saturated. SP Light brown, brown fine grained sand with some silt and some gravel. Damp and dense. End of sub -surface exploration 16 feet.Groundwater was not observed within 16 feet. icts conditions at the time and location drilled. Soil Pacific Inc. Project Name: APN 770-156-006 Calle Cadiz, La Quinta. Ca. Geotechnical and Environmental project Number: A-6841-19 Services Rcoort Date: Figure: Log of Sub -surface Exploration C Std. Pen Drive USCS Letter Equipment Type: ASM Boring # B-2 Wt: Bulk/Bag Drop: Graphic Diameter: 4" Logged by: A.Sh. Date:2/14/19 Depth: 12 feet G.water: - Backfilled:Y Ring Laboratory Description of Earth Materials Elev. (feet) Moistur Dry N Reading SM Light brown, fine grained silty sand, and sand, damp to moist, top soil. - 4.8 110.7 SP Light brown, fine to medium grained sand with tarce of silt damp to dry, native. 5- Light brown to brown suger sand, saturated. - 4.0 110 SP 10 - SP Light brown, brown fine grained sand with some silt and some - gravel. Damp and dense. 15- 20- - End of sub -surface exploration 12 feet. 25- 30- 35- 40-1111 Log depicts conditions at the time and location drilled. Soil Pacific Inc. Geotechnical and Environmental Services Proiect Name: APN 770-156-006 Calle Cadiz, La Proiect Number: A-6841-19 Report Date: Figure: Ca. APPENDIX B Laboratory 0 2 LL- cn Y H C7 z W Q �-- 1. cn 1 5 n AIPPF�NE-) 2 X SHEAR TEST DIAGRAM J.O. A-6841-19 3 B-2 at 3 eet Sand COHESION 255 PSF PHI = 31 EGREES 5 5 0 .5 1.0 1.5 2.0 2.5 3.0 DATE 2/1.11/19 NORMAL PRESSURE KSF PLATE .`�,PP='E:r-,Jo = x BEARING VALUE ANALYSIS J.O. A-5841-19 COHESION = 255 PSF GAMA = 120 PCF DEPTH OF FOOTING = 2 FEET BREADTH OF FOOTING = 2 FEET FOOTING TYPE = SQUARE DATE 2/14/19 PHI = 31 DEGREES BEARING CAPACITY FACTORS Nc = 32.7 Nq - 20.6 Ng = 21.6 FOOTING COEFFICIENTS K1 = 1.2 K2 = .4 REFERENCE: TERZAGHI 6 PECK; 1967: 'SOIL MECHANICS IN ENGINEERING PRACTICE'; PAGES 217 TO 225. FORMULA ULIMATE BEARING = (K1 * Nc * C) + (K2 * GA * Ng * B) + (Nq * GA * D) - 17024.9 _ ALLOWABLE BEARING_= ULTIMATE_BEARING_=_ 3 THE ALLOWABLE BEARING VALUE SHOULD NOT EXCEED 5675 PSF. DESIGN SHOULD CONSIDER EXPANSION INDEX. PLATE f# BEARING VALUE ANALYSIS J.O. A-6841-19 DATE 2/14/19 COHESION = 255 PSF GAMA = 120 PCF PHI = 31 DEGREES DEPTH OF FOOTING = 2 FEET BREADTH OF FOOTING = 1.5 FEET FOOTING TYPE = CONTINUOUS BEARING CAPACITY FACTORS Nc = 32.7 Nq = 20.5 Ng = 21.6 FOOTING COEFFICIENTS K1 = 1 K2 = .5 REFERENCE: TERZAGHI 6 PECK: 1967: 'SOIL MECHANICS IN ENGINEERING PRACTICE'. PAGES 217 TO 225. FORMULA ULIMATE BEARING = (K1 * Nc * C) + (K2 * GA * Ng * B) + (Nq * GA * D) - 15228.9 ALLOWABLE BEARING = ULTIMATE BEARING = ,5076._3 _ 3 THE ALLOWABLE BEARING VALUE SHOULD NOT EXCEED 5076.3 PSF. DESIGN SHOULD CONSIDER EXPANSION INDEX. PLATE A F= F= E= 1-J ED S X TEMPORARY BACKCUT STABILITY J.O. A-6841-19 DATE 2/14/19 COHESION = 255 PSF LAMA = 120 PCF PHI = 31 DEGREES CUT HEIGHT = 4 FEET SOIL TYPE = Silty sand BACKFILL ASSUMED TO BE LEVEL PORE PRESSURE NOT CONSIDERED FORMULA SAFETY FACTOR = (C * L) + (GA AREA * COS (Z) * TAN (PHI) ) - 2.82 GA * AREA * SIN(Z) Z = 45 + (PHI/2) SINCE THE SAFETY FACTOR OF 2.82 IS GREATER THAN THE REQUIRED 1.25, THE TEMPORARY EXCAVATION IS CONSIDERED TO BE STABLE. THIS IS WITH A LEVEL AREA EQUAL TO THE LENGTH OF THE VERTICAL CUT ABOVE THE CUT. PLATE APPENDIX C References LEGEND Soil Boring Location Desert Club Dr 20 161;2� 8 f Q n 40 Feet Graphk scale :oil PFIzIFIC Inc. Geotechnical & Environmental Services 675 N. Eckhoff, Suite # A Orange, CA 9286E Project Location: Calle Cadiz APN 770-156-006 GEOTECHNICAL PLAN FIGURE-A-1-1 I PROJECT NO.: A-6841-19 I DATE: 02/14/2019 SHEET 1 OF 1 AMERICAN SOCIETY 0E OW ENGINEERS Address: 78175 Calle Cadiz La Quinta, California 92253 ASCE 7 Hazards Report Standard: ASCE/SEI 7-16 Elevation: 45.12 ft (NAVD 88) Risk Category: III Latitude: 33.674919 Soil Class: D - Default (see Longitude:-116.300638 Section 11.4.3) W►tt . . . w V ! 16 �'� I• y38 } I.I r•sf • Ir • � I } . h . s La Quinta -T- f. �NFr•�Y I iLll _•rlinq� �� �Ir • rr•j r-.vn„am ;err, Clly ■� wh !ur•ry rJi•y lr .nV Taim P—rt tnrHn:• � � \ COA C MELiA l'A LC;Er Pwk Rxl O AIOUNIA/NS ' i https:/lasce7hazardtool.online/ Page 1 of 3 Thu Feb 14 2019 E' AME IM SOCIETY OF CIVIL RON®TS Seismic Site Soil Class: D - Default (see Section 11.4.3) Results: SS : 1.5 So, N/A S, 0.6 TL 8 Fe 1.2 PGA: 0.593 F„ N/A PGA M : 0.712 SMS 1.8 FPGA 1.2 SM1 N/A IB : 1.25 Sos 1.2 C„ : 1.4 Ground motion hazard analysis may be required. See ASCE/SET 7-16 Section 11.4.8. Data Accessed: Thu Feb 14 2019 Date Source: USGS Seismic Design Mans h(t s:/1asce?hazardtaol.onHne Page 2 of 3 Thu Feb 14 2019 E' AMEERICAN SOCIETY OF CPJIL ENGINEERS The ASCE 7 Hazard Tool is provided for your convenience, for informational purposes only, and is provided "as is" and without warranties of any kind. The location data included herein has been obtained from information developed, produced, and maintained by third party providers; or has been extrapolated from maps incorporated in the ASCE 7 standard. While ASCE has made every effort to use data obtained from reliable sources or methodologies, ASCE does not make any representations or warranties as to the accuracy, completeness, reliability, currency, or quality of any data provided herein. Any third -party links provided by this Tool should not be construed as an endorsement, affiliation, relationship, or sponsorship of such third -party content by or from ASCE. ASCE does not intend, nor should anyone interpret, the results provided by this Tool to replace the sound judgment of a competent professional, having knowledge and experience in the appropriate field(s) of practice, nor to substitute for the standard of care required of such professionals in interpreting and applying the contents of this Tool or the ASCE 7 standard. In using this Tool, you expressly assume all risks associated with your use. Under no circumstances shall ASCE or its officers, directors, employees, members, affiliates, or agents be liable to you or any other person for any direct, indirect, special, incidental, or consequential damages arising from or related to your use of, or reliance on, the Tool or any information obtained therein. To the fullest extent permitted by law, you agree to release and hold harmless ASCE from any and all liability of any nature arising out of or resulting from any use of data provided by the ASCE 7 Hazard Tool. ht1 s:llasce7hazardtool.ontinet Page 3 of 3 Thu Feb 14 2019 APPENDLX D General Grading Specifications GENERAL EARTHWORK AND GRADING SPECIFICATIONS L GENERAL INTENT These specifications present general procedures and requirements for grading and earthwork as shown on the approved grading plans, including preparation of areas to be filled, placement of fill, installation of subdrains, and excavations. The recommendations contained in the geotechnical report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations of the geotechnical report. 2.EARTHWORK OBSERVATION AND TESTING Prior to the commencement of grading, a qualified geotechnical consultant (soils engineer and engineering geologist, and their representatives) shall be employed for the purpose of observing earthwork and testing the fills for conformance with the recommendations of the geotechnical report and these specifications. It will be necessary that the consultant provide adequate testing and observation so that he may determine that the work was accomplished as specified. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes so that he may schedule his personnel accordingly. 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, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the consultant will be empowered to reject the work and recommend that construction be topped until the conditions are rectified. Maximum dry density tests used to determine the degree of compaction will be performed in accordance with the American Society of Testing and Materials tests method ASTM D 1557-00. 3.0 PREPARATION OF AREAS TO BE FILLED 3.1 Clearing and Grubbing: All brush, vegetation and debris shall be removed or piled and otherwise disposed of. 3.2 Processing: The existing ground which is determined to be satisfactory for support of fill shall be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform and free of uneven features which would inhibit uniform compaction. 3.3 Overexcavation: Soft, dry, spongy, highly fractured or otherwise unsuitable ground, extending to such a depth that the surface processing cannot adequately improve the condition, shall be overexcavated down to firm ground, approved by the consultant. 3.4 Moisture Conditioning: Overexcavated and processed soils shall be watered, dried -back, blended, and/or mixed, as required to attain a uniform moisture content near optimum. 3.5 Recompaction: Overexcavated and processed soils which have been properly mixed and moisture- conditioned shall be recompacted to a minimum relative compaction of 90 percent. 3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5: 1(horizontal to vertical units), the ground shall be stepped or benched. The lowest bench shall be a minimum of 15 feet wide, shall be at least 2 feet deep, shall expose firm material, and shall be approved by the consultant. Other benches shall be excavated in firm material for a minimum width of 4 feet. Ground sloping flatter than 5 : 1 shall be benched or otherwise overexcavated when considered necessary by the consultant. 3.7 Approval: All areas to receive fill, including processed areas, removal areas and toe -of -fill benches shall be approved by the consultant prior to fill placement. 4.0 FILL MATERIAL 4.1 General: Material to be placed as fill shall be free of organic matter and other deleterious substances, and shall be approved by the consultant. Soils of poor gradation, expansion, or strength characteristics shall be placed in areas designated by consultant or shall be mixed with other soils to serve as satisfactory fill material. 4.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 12 inches, shall not be buried or placed in fills, unless the location, materials, and disposal methods are specifically approved by the consultant. Oversize disposal operations shall be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 feet vertically of finish grade or within the range of future utilities or underground construction, unless specifically approved by the consultant. 4.3 Import: if importing of fill material is required for grading, the import material shall meet the requirements of Section 4. 1. 5.0 FILL PLACEMENT AND COMPACTION 5.1 Fill Lifts: Approved fill material shall be placed in areas prepared to receive fill in near -horizontal layers not exceeding 6 inches in compacted thickness. The consultant may approve thicker lifts if testing indicates the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to attain uniformity of material and moisture in each layer. 5.2 Fill Moisture: Fill layers at a moisture content less than optimum shall be watered and mixed, and wet fill layers shall be aerated by scarification or shall be blended with drier material. Moisture -conditioning and mixing of fill layers shall continue until the fill material is at a uniform moisture content or near optimum. 5.3 Compaction of Fill: After each layer has been evenly spread, moisture conditioned, and mixed, it shall be uniformly compacted to not less than 90 percent of maximum dry density. Compaction equipment shall be adequately sized and shall be either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree of compaction. 5.4 Fill Slopes: Compaction of slopes shall be accomplished, in addition to normal compacting procedures, by backfilling of slopes with sheepsfoot rollers at frequent increments of 2 to 3 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the slope out to the slope face shall be at least 90 percent. 5.5 Compaction Testing: Field tests to check the fill moisture and degree of compaction will be performed by the consultant. The location and frequency of tests shall be at the consultant's discretion. In general, the tests will be taken at an interval not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of embankment. 6.0 SUBDRAIN INSTALLATION Subdrain systems, if required, shall be installed in approved ground to conform to the approximate alignment and details shown on the plans or herein. The subdrain location or materials shall not be changed or modified without the approval of the consultant. The consultant, however, may recommend and upon approval, direct changes in subdrain line, grade or material. All subdrains should be surveyed for line and grade after installation, and sufficient time shall be allowed for the surveys, prior to commencement of filling over the subdrains. 7.0 EXCAVATION Excavation and cut slopes will be examined during grading. If directed by the consultant, further excavation or overexcavation and refilling of cut areas shall be performed, and/or remedial grading of cut slopes shall be performed. Where fill -over -cut slopes are to be graded, unless otherwise approved, the cut portion of the slope shall made and approved by the consultant prior to placement of materials for construction of the fill portion of the slope. 8.0 TRENCH BACKFILLS 8.1 Supervision: Trench excavations for the utility pipes shall be backfilled under engineering supervision. 8.2 Pipe Zone: After the utility pipe has been laid, the space under and around the pipe shall be backfilled with clean sand or approved granular soil to a depth of at least one foot over the top of the pipe. The sand backfill shall be uniformly jetted into place before the controlled backfill is placed over the sand. 8.3 Fill Placement:'The onsite materials, or other soils approved by the engineer, shall be watered and mixed as necessary prior to placement in lifts over the sand backfill. 8.4 Compaction: The controlled backfill shall be compacted to at least 90 percent of the maximum laboratory density as determined by the ASTM compaction method described above. 8.5 Observation and 'Testing: Field density tests and inspection of the backfill procedures shall be made by the soil engineer during backfilling to see that the proper moisture content and uniform compaction is being maintained. The contractor shall provide test holes and exploratory pits as required by the soil engineer to enable sampling and testing.