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Home My WebLink AboutMS 02-05; CARLSBAD OCEANVIEW ESTATES; ROUGH GRADING RREPORT; 2022-05-09 ADVANCED GEOTECHNICAL SOLUTIONS, INC. 485 Corporate Drive, Suite B Escondido, California 92029 Telephone: (619) 867-0487 Fax: (714) 409-3287 ADVANCED GEOTECHNICAL SOLUTIONS, INC. HENRY OLIVIER May 9, 2022 4370 Hallmark Pkwy, Ste. 101 P/W 2203-04 San Bernardino, CA 92408 Report No. 2203-04-C-2 Attention: Henry Olivier Subject: Rough Grading Report, Parcels 1 Through 3, Carlsbad Oceanview Estates, 0 Adams Street, Carlsbad, California References: See Attached In accordance with your request and authorization, Advanced Geotechnical Solutions, Inc., (AGS) presents herein an interim report summarizing our observations and test results for the current rough grading of Parcels 1 through 3, Carlsbad Oceanview Estates, 0 Adams Street, Carlsbad, California. Based on the results of the testing and observations by representatives of AGS, the work described herein is considered to be in general conformance with City of Carlsbad Grading Code and the recommendations presented in the referenced geotechnical report. Rough grading for the subject site, under the purview of this report, was conducted from March 2022 to April 2022. Soil engineering observations, density and laboratory test results performed through April 4, 2022, are summarized in the text of this report and the developed data are presented in Table I. AGS has plotted the approximate locations of geologic units, formational contacts, removal elevations, and approximate locations of density tests collected during rough grading on the enclosed Plate 1 (Sheet 3 of 4). This sheet is based upon the 20-Scale Rough Grading Plans for Carlsbad Oceanview Estates, (Sheet 3 of 4), dated August 18, 2021, prepared by Fusion Engineering & Technology (FET) as a base. Future site grading, trench backfill, surface and appurtenant improvements must be performed in accordance with local governing agency requirements and the recommendations of a qualified Geotechnical Engineer. 1.0 GEOLOGY 1.1. Regional Geologic and Geomorphic Setting The subject site is situated within the Peninsular Ranges Geomorphic Province. The Peninsular Ranges province occupies the southwestern portion of California and extends southward to the southern tip of Baja California. In general, the province consists of young, steeply sloped, northwest trending mountain ranges underlain by metamorphosed Late Jurassic to Early Cretaceous-aged extrusive volcanic rock and Cretaceous-aged igneous plutonic rock of the Peninsular Ranges Batholith. The westernmost portion of the province, where the subject site is located, is predominantly underlain by younger marine and non-marine sedimentary rocks. The Peninsular Ranges’ dominant structural feature is northwest-southeast trending crustal blocks bounded by active faults of the San Andreas transform system. ~GS May 9, 2022 Page 2 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. 1.2. Subsurface Conditions A brief description of the earth materials encountered during grading operations for this portion of the site is presented in the following sections. Based on the referenced reports and our observations during site grading, the site was discontinuously mantled with a thin layer of residual soils underlain to depth with Old Paralic Deposits. 1.2.1. Surficial Soils (No Map Symbol) As encountered these materials generally consisted of topsoil and residual soil that was reddish brown to grayish brown, fine-grained sand to silty sand in a dry and loose condition. The surficial soils were generally one foot thick and were removed as encountered as part of rough grading operations. 1.2.2. Old Paralic Deposits (Map Symbol Qop) The site is underlain to the maximum depths explored by Old Paralic Deposits. These materials as encountered can generally be described as reddish brown to dark yellow brown, fine-grained sand to silty sand with trace clay, in a damp to moist and moderately dense to very dense condition. Portions of the Old Paralic Deposits exhibited a weathered/residual soil horizon ranging from one to two feet thick. 1.3. Faults The site is not located within an Alquist-Priolo Earthquake Fault Zone. No evidence of active faulting was observed within the subject site during rough grading. 1.4. Groundwater Groundwater was not encountered during grading within the subject site. It should be noted that water may develop at a later date, due to fluctuations in precipitation, irrigation practices, or factors not evident at the time of grading. 1.5. Subdrains Canyon-type subdrains were not considered necessary due to the shallowness of engineered fill placed during rough grading. 1.6. Liquefaction Potential Based upon AGS's observations during the rough grading, the hardness of the bedrock, the density of the compacted fill and the lack of groundwater encountered onsite, the potential for liquefaction is considered to be very low. 2.0 GRADING Presented herein is a summary of observations collected during site grading. Geotechnical observation and testing services were provided on an as-requested basis. Prior to rough grading the subject site consisted of rolling to moderately steep hills with a light growth of seasonal grasses. Prior to the commencement of May 9, 2022 Page 3 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. grading operations, the existing onsite surface vegetation within the proposed limits of grading was cleared, grubbed and disposed of offsite. Based on the referenced geotechnical report, it was concluded that remediation of the upper surface soils, where not removed by design cuts, would be required during site grading operations. Additional remedial grading measures such as overexcavation for future improvements was not performed. Presented herein is a summary of the removal and fill placement operations. 2.1. Unsuitable Soil Removals Grading for the subject site consisted of rough grading areas as depicted on the 20-scale grading plans, prepared by FET. Prior to placement of fill on the site, the compressible pre-existing surficial soils and highly weathered portions of formational materials were removed. Unsuitable soils removals below the toe of the fill slopes extended from the catch point of the design toe outward at a minimum 1:1 projection (where possible) into approved material. Removal bottom locations and elevations presented herein were determined utilizing information provided by the grading contractor’s field personnel utilizing field staking and laser level. The removal depths for the subject site generally ranged from approximately two (2) to four (4) feet below existing grades. Removal bottom elevations are shown on Plate 1, included herewith. The removal bottoms were observed and approved by representatives of AGS. The exposed removal bottoms were then scarified to an approximate depth of 6 to 8 inches, brought to or slightly above optimum moisture content and compacted to the minimum project standard of the laboratory maximum dry density in accordance with ASTM Test Method D-1557. 2.2. Compaction Operations Compaction test results are presented in Table I. Approximate test locations are shown on the enclosed Compaction Test Plans. Compaction testing was conducted utilizing portable nuclear gauges (ASTM D6938). Compaction tests were taken during the course of grading at approximately every one to two feet of fill placed. Fill consisting of the soil types indicated in Table I was placed in lifts, moisture conditioned to optimum moisture content, or slightly above, and compacted to a minimum 90 percent of the laboratory maximum dry density (ASTM:D 1557). Compaction was accomplished by equipment wheel rolling with a Cat 945 loader along with other heavy earth moving equipment. Each succeeding fill lift was treated in a similar manner. 2.3. Slopes The following comments are regarding the construction of fill slopes, cut slopes, and natural slopes. 2.3.1. Fill Slopes Fill slopes were graded to a maximum height of approximately 8 feet. Unsuitable soils removals below the toe of the fill slopes extended from the catch point of the design toe outward at a minimum 1:1 projection (where possible) into approved material. May 9, 2022 Page 4 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. Fill slopes were generally constructed by overfilling not less than one to two feet, measured horizontal to the slope face. The slope was then trimmed back to the compacted core of engineered fill. 2.3.2. Natural Slopes A natural slope was left in place on the east side of the property. This cut slope is considered grossly stable. . 2.3.3. Cut Slopes Cut slopes were graded at slope ratios of 2:1 (horizontal:vertical) to maximum heights of approximately 20 feet. The completed cut slopes were observed and geologically mapped for significant geologic features exposed. The cut slopes were determined to be grossly and surficially stable as graded. 2.3.4. Stability of Slopes Based on the compaction tests results and observations collected during the rough grading operations, it is AGS’s opinion that the fill and cut slopes constructed under the purview of this report are considered to be grossly and surficially stable at this time and should remain so under normal conditions. As is the case with any graded slope, proper drainage, maintenance, and landscaping are essential to long-term performance and should be implemented as soon as possible. 2.3.5. Nuisance Slope Seepage and Slope Maintenance Precipitation and/or landscape irrigation (post-grading) could create a nuisance seepage condition on graded slopes to the extent that it may require collection devices to be installed by homeowners and/or the HOA. This can be mitigated by constructing interceptor drains and should be handled on a case-by-case basis. 3.0 SLOPE AND LOT MAINTENANCE The onsite soils are considered highly erosive. It is imperative that temporary erosion control devices/systems be installed as soon as possible and maintained until full landscaping and permanent erosion control are established. Erosion control features may include installation of silt fencing, fiber rolls/straw wattles, and spraying slopes with bonded fiber matrix. Consultation with a contractor that specializes in erosion control is recommended. Maintenance of improvements is essential to the long-term performance of structures and slopes. Although the design and construction during mass grading created slopes that are considered both grossly and surficially stable, certain factors are beyond the control of the soil engineer and geologist. The homeowners must implement certain maintenance procedures. May 9, 2022 Page 5 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. 3.1. Slope Planting Slope planting should consist of ground cover, shrubs and trees that possess deep, dense root structures and require a minimum of irrigation. The resident should be advised of their responsibility to maintain such planting. 3.2. Site Drainage Roof, pad and lot drainage should be collected and directed away from structures and slopes and toward approved disposal areas. Design fine-grade elevations should be maintained through the life of the structure, or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water away from structures and slopes. Residents should be made aware that they are responsible for maintenance and cleaning of all drainage terraces, downdrains, and other devices that have been installed to promote structure and slope stability. 3.3. Slope Irrigation The resident, homeowner and/or Homeowner Association should be advised of their responsibility to maintain irrigation systems. Leaks should be repaired immediately. Sprinklers should be adjusted to provide maximum uniform coverage with a minimum of water usage and overlap. Overwatering with consequent wasteful run-off and ground saturation should be avoided. If automatic sprinkler systems are installed, their use must be adjusted to account for natural rainfall conditions. 3.4. Subsurface Drains Subsurface drains consisting of keyway heel drains or toe drains may be constructed during future site grading. Any constructed drains should be outletted to the future storm drain system or into v-gutters. These drains must be repaired if damaged and must be maintained during the life of the development. The owners/homeowner’s association should maintain the subdrains and their outlets. 3.5. Burrowing Animals Residents or homeowners should undertake a program for the elimination of burrowing animals. This should be an ongoing program in order to maintain slope stability. 4.0 FUTURE IMPROVEMENTS Provisions need to be incorporated into the construction and inspection of all future grading and improvements within the subject site to account for the hillside nature for the project, as well as being designed to account for potential expansive soil conditions. Design considerations on any given area may need to include provisions for differential bearing materials (formation vs compacted fill), ascending/descending slope conditions, geologic structure, perched (irrigation) water, special surcharge loading conditions, potential expansive soil pressure and differential settlement/heave. All site improvements should be designed and constructed by qualified professionals using appropriate design methodologies that account for the onsite soils and geologic conditions. The aforementioned May 9, 2022 Page 6 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. considerations should be used when designing, constructing, and evaluating long term performance of the exterior improvements on the lots. 5.0 LIMITATIONS This report presents information and data relative to interim mass grading operations for the subject site. A representative(s) of this firm probed and tested at random locations in an effort to determine whether compliance with the project compaction, specifications, and applicable Building Code was being obtained. The presence of our personnel during grading operations does not involve any supervision or direction of the contractor or his work forces. Elevations and locations of removal bottoms, subdrains and keyways mapped herein were provided to AGS by the Grading Contractors based upon their Global Positioning System (GPS). Staking was not provided and AGS relied on the contractor to provide locations and elevations in the field. AGS does not provided surveying services and, therefore, expresses no opinion regarding the accuracy of the contractor’s GPS provided locations and elevations. The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to contact the undersigned. Respectfully Submitted, Advanced Geotechnical Solutions, Inc. Prepared by STEVEN L. JESSUP Staff Engineer Reviewed by ___________________________________ __________________________________ JOHN J. DONOVAN PAUL J. DERISI RCE 65051/GE 2790, Reg. Exp. 6-30-23 CEG 2536, Reg. Exp. 5-31-23 2203-04-C-2 (RGR 4-29-22) Distribution: (1) Addressee Enclosed: Appendix A- Reference Table I- Compaction Test Table Plate 1 (Sheet 3 of 4) May 9, 2022 Page 7 P/W 2203-04 Report No. 2203-04-C-2 ADVANCED GEOTECHNICAL SOLUTIONS, INC. REFERENCES Fusion Engineering and Technology (2021). 20-Scale Rough Grading and Plans for Carlsbad Oceanview Estates, Carlsbad, California. Geotechnical Solutions, Inc. (2006). “Geotechnical Engineering Update Report, Approximately 1.15-acre Parcels, NE Corner of Adams & Hoover Streets, Carlsbad, California,” dated January 31, 2006 (Project No. G-1845-06). ---. (2001). “Preliminary Geotechnical Engineering Study, Approximately 1.15-Acre Parcels, NE Corner of Adams and Hoover Streets, Carlsbad, California,” dated June 22, 2001 (Project No. G-1845-06). Wyland, Todd R., Civil Engineer (2020). “Retaining Wall Back Cuts, NE Corner of Hoover & Adams Streets, Carlsbad, California,” dated August 12, 2020 (Project No. 147G). ---. (2017). “Update to Preliminary Geotechnical Engineering Study Report, NE Corner of Hoover & Adams Streets, Carlsbad, California,” dated November 20, 2017 (Project No. 147G). May 9, 2022 P/W 2203‐04 SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TABLE I Page 1 of Table I Report No. 2203‐04‐C‐2 SOIL TYPE DESCRIPTION OPTIMUM MOISTURE CONTENT (%) MAXIMUM DRY DENSITY (pcf) A Reddish brown SM 9.0 129.0 ADVANCED GEOTECHNICAL SOLUTIONS, INC. May 9, 2022 P/W 2203‐04 FIELD DENSITY TEST RESULTS TABLE 1 (cont'd) Page 2 of Table I Report No. 2203‐04‐C‐2 Depth Rel. Proj. Test Pass Test or Soil Rock Comp. Spec. Type or Date Number Location Elev. Type Corr.* Opt.* Field Max.* Field (%) (%) (S/N) Fail 03/24/22 101 Upper Key Parcel 3 94 A 9.0 10.0 129.0 116.5 90 90 N Pass 03/24/22 102 Upper Key Parcel 2 84 A 9.0 10.5 129.0 117.0 90 90 N Pass 03/30/22 103 Lower Key Parcel 3 62.5 A 9.0 9.6 129.0 118.4 91 90 N Pass 03/30/22 104 Lower Key Parcel 3 62.5 A 9.0 9.1 129.0 119.5 92 90 N Pass 03/30/22 105 Lower Key Parcel 1 63 A 9.0 9.9 129.0 118.1 91 90 N Pass 03/30/22 106 Lower Key Parcel 1 65 A 9.0 9.4 129.0 117.6 91 90 N Pass 03/30/22 107 Lower Key Parcel 2 66 A 9.0 10.2 129.0 119.0 92 90 N Pass 03/31/22 108 Parcel 1 69 A 9.0 10.1 129.0 114.0 88 90 N Fail 03/31/22 109 Parcel 3 67 A 9.0 9.4 129.0 119.0 92 90 N Pass 03/31/22 108‐R Parcel 1 69 A 9.0 9.4 129.0 117.1 90 90 N Pass 04/01/22 110 Parcel 2 64 A 9.0 9.6 129.0 119.3 92 90 N Pass 04/01/22 111 Parcel 1 68 A 9.0 9.7 129.0 118.9 92 90 N Pass 04/04/22 112 Parcel 1 70 A 9.0 10.3 129.0 117.3 90 90 N Pass 04/04/22 113 Parcel 1 71 A 9.0 9.6 129.0 119.4 92 90 N Pass 04/04/22 114 Middle Key Key Parcel 1 76 A 9.0 9.2 129.0 120.3 93 90 N Pass 04/04/22 115 Middle Key Key Parcel 1 75 A 9.0 9.5 129.0 122.4 94 90 N Pass (pcf) Moisture (%) TEST NUMBER/LOCATION/ELEVATION KEY S ‐ Sewer Trench I ‐ Irrigation Trench SD ‐ Storm Drain Trench E ‐ Electrical Trench JT ‐ Joint Utility Trench W ‐ Water Trench RT ‐ Retaining Wall FT ‐ Footing FG ‐ Finish Grade SW ‐ Sidewalk SG ‐ Subgrade CG ‐ Curb and Gutter B ‐ Base BG ‐ Base Grade AC ‐ Asphalt Concrete Finish Grade BC ‐ Asphalt Concrete Base Course CC ‐ Asphalt Concrete Cap Course ‐R,R1,R2 ‐ Indicates Retest * Rock Correction‐ Estimated Percent Retained on 3/4 inch (Method C), Maximum Dry Density and Optimum Moisture Content adjusted per ASTM D 4718; S: Sad Cone; N:Nuclear Density Gauge Dry Density ADVANCED GEOTECHNICAL SOLUTIONS, INC. afe (Qop) 105 113 112 106 108108R 104 109 107 10361.061.0 63.057.058.0 60.0 61.0 62.0 115 114 80.0 80.0 75.0 78.0 76.0 72.0 71.0 78.0 85.0 83.0 83.0 89.0 96.0102101 afe (Qop) QopQop afe (Qop) afe (Qop) 111 110 LEGEND ARTIFICIAL FILL-ENGINEERED OLD PARALIC DEPOSITS (BRACKETED WHERE BURIED) APPROXIMATE LOCATION OF GEOLOGIC CONTACT APPROXIMATE LOCATION AND ELEVATION OF REMOVAL BOTTOM APPROXIMATE LOCATION OF FIELD DENSITY TEST afe Qop 57.0 101 --- • 60.8 -.1" 01 EX. 10' WATER PER DWG. #278-4 UNDERGROUND SERVICE ALERT EX. 8' WATER PER -----4 DWG. #278-4 FUSION ENG TECH 1810 GILLESPIE WAY t207 EL CAJON, CA 92020 CALL: TOLL FREE 1-800 227-2600 PR BY_ (619) 736-2800 TWO WORKING DAYS BEFORE YOU DIG ad, 08/10/2021 DATE: I I - ---I 1----, ' -' ---6Q------___ I ' 20 0 20 40 SCALE 1"=20' LEGEND DWG.NO. DESCRIPTION UNIT QUANTIT1 1 CONSTRUCT BROW DITCH PER S.D.R.S.D. #D-75, TYPE B (TYPE D WHEN PLACED DOWN SLOPE). LF 560 2 CONSTRUCT TEMPORARY SEDIMENTATION BASIN PER DETAIL BELOW. EA 3 3 CONSTRUCT 4'X4' RIP-RAP, NO. 2 BACKING, 8" THICKNESS PER S.D.R.S.D. #D-40 EA 6 4 CONSTRUCT 4'X8' RIP-RAP, NO. 2 BACKING, 8" THICKNESS PER S.O.R.S.D. #D-40 EA 7 5 CONSTRUCT EARTHEN SWALE W=4' & 0=1'. LF 650 6 CONSTRUCT 12"X12" CATCH BASIN -PER BROOKS BOX OR EQUIV. EA 3 7 INSTALL 6" PVC PIPE. LF 35 ® FUTURE PERMANENT BMP WATER QUALITY FACILITY SIGN TO BE INSTALLED BY OWNERS EA W / FUTURE BIORETENTION BASIN SEE SHEET 4. 3 (9 CONSTRUCT CONCRETE SPLASH WALL PER DETAIL ON SHEET 2. EA 3 SEDIMENTATION BASIN AREAS BMP SUMMARY TABLE FOR PROJECTED BASIN SIZES FOR FUTURE CONSTRUCTION NOTE TYPE AREA (SF) SEDIMENT BASIN 157 FT-4-1 SEDIMENT BASIN 151 FT-4-2 SEDIMENT BASIN 1 61 FT-4-3 BASIN ULTIMATE FINISH GRADE 7.5' OWNERSHIP HEN RY OLIVIER HENRY OLIVIER HENRY OLIVIER TYPE PARTIAL RETENTION BY BIOFILTRATION BASIN PR-1-1 PARTIAL RETENTION BY BIOFILTRATION BASIN PR-1-2 PARTIAL RETENTION BY BIOFILTRATION BASIN PR-1-3 ®PROPOSED 12"X12" C.B. FOR OVERFLOW PORTION OF RISER ABOVE FINISH GRADE TO BE WRAPPED IN PERMEABLE LINER (MIRAFI 140N OR EQUIVALENT) TO PREVENT CLOGGING OF ORIFICE HOLES AND/OR SEDIMENT TRANSPORT TO DISCHARGE SUBDRAIN 7.5' PLATE 1 BASIN ULTIMATE FINISH GRADE TEMPORARY SEDIMENTATION BASIN@ NOT TO SCALE NOT TO SCALE CONSTRUCTION NOTE CONCEPTUAL WATER QUALITY BASIN TO BE INSTALLED IN FUTURE BY OWNER ONCE PRECISE GRADING PERMITS ARE APPROVED FOR HOUSE CONSTRUCTION. "ASSUMPTION OF RESPONSIBLE CHARGE" AS OF OS/l l/202 l , I HEREBY ASSUME RESPONSIBLE CHARGE AREA (SF) 262 260 226 OWNERSHIP HENRY OLIVIER HENRY OLIVIER HENRY OLIVIER 0 PROPOSED 6" PVC TO STREET PARKWAY DRAIN "AS BUILT" ~~GS ADVA.NCED GEOTECHNICAL SOLUTIONS, INC. 485 Corporate Drive, Suite B Escondido, Californi a 92029 Tclcpho11c: (714) 786-5661 Fax: (714) 409-3287 (/4',1 fJ#aA. RCE# 733878 EXP. 06/30/23 ~ R THE DESIGN OF THIS DRAWING. <lii S. Rlv'ERA RCE __ _ EXP ____ _ DATE REVIEWED BY: 60 Report# 2203-04-C-2 Date: MAY 2022 FIRM: FUSION ENGINEERING AND TECHNOLOGY PHONE: (619)736-2800 ADDRESS: 1810 GILLESPIE WAY, SUITE 207 -EL CAJON, CA 92020 INSPECTOR DATE l---+---l-------------+--+--+---+----I I SH3EET I CITY OF CARLSBAD I SH4EETS I ENGINEERING DEPARTMENT ;;:G;:;R;:;A:;;D:;;IN:.;G;_:;;P;LAN:;:;S;:;F;:;O;:;R~: =========:'...=:==~ 08/10/2021 1 REM HOOSES, REV PG TO RG. REPLACE SHT 3 8-11-21 DER DATE DATE INITIAL DATE INITIAL ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL CITY APPROVAL CARLSBAD 0CEANVIEW ESTATES ROUGH GRADING & DRAINAGE PLAN GR-2016-0030 HDP02-04/CDP02-16 APPROVED: JASON S. GELDERT r,,,. 0ew,«/P• 8/1812021 ENGINEERING MANAGER RCE 63912 EXPIRES 9 30 22 DATE OWN BY: -"..W-'- CHKD BY; __ _ RVWD BY: PROJECT NO. MS-02-D5 I DRAWING NO. 438-2A