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Home My WebLink AboutSDP 2020-0005; CHILDREN'S PARADISE PRESCHOOL; FINAL SOILS REPORT; 2025-08-18Project No. FC-23-04-124 August 18, 2025 Ms. Julie Lowen Children's Paradise 211 Main Street, Suite 205 Vista, California 92084 6116 GEOTECHNICAL SOLUTIONS, INC. Consulting Geotechnical Engineers 3129 Tiger Run Court, Suite 111 Carlsbad, California 92010 Office: (760) 602-7815 smsgeosol.inc@gmail.com Subject: Final Report of Grading Observations and Soil Testing New Children's Paradise Preschool Marron Road, Carlsbad, California (Project No. SDP2020-0005, Drawing No. 536-?A) Per the request of Mr. Jerry Condron and as required by the City of Carlsbad, 6116 Geotechnical Solutions, Inc. hereby presents this final report of grading observations and soil testing performed on subject property. Our firm previously issued a Report of As- Graded Geotechnical Engineering Observations and Compaction Testing for the subject project on June 10, 2023. Our firm also prepared a Report of Geotechnical Investigation And Borehole Percolation Testing report dated January 29, 2019 and the following additional supplementary documentation: 1. "Response to City of Carlsbad Review Comments, Geotechnical Addendum, Delta 2 Construction Change, Planned Eastern Short Retaining Wall Along The Walmart Property Boundary, Children Paradise Preschool, Marron Road, Carlsbad, California," Project No. FC-23-04-124, dated November 14, 2024 2. "Geotechnical Addendum, Delta 2 Construction Change, Planned Eastern Short Retaining Wall Along The Walmart Property Boundary, Children Paradise Preschool, Marron Road, Carlsbad, California," Project No. FC-23-04-124, dated November 4, 2024 3. "Geotechnical Foundation Plan Review, Proposed Shade Structures, Children Paradise Preschool, Marron Road, Carlsbad, California," Project No. FC-23-04-124, dated October 5, 2024 R18 C1077 D3740 E329 AASH I □ ACCREDITED Final Report of Grading Observations and Soil Testing August 18, 2025 Marron Road, Carlsbad (Project No. SDP2020-0005, Drawing No. 536-7A) Page 2 4. "Geotechnical Plan Review And Response to Third-Party Review Comments, Proposed Children Paradise Preschool, Quarry Creek Development, Marron Road, Carlsbad, California," prepared by 6M.6Geotechnical Solutions, Inc., Project No. Gl- 19-11-155, dated May 28, 2022 5. "Geotechnical Foundation Plan Review, Proposed Children Paradise Preschool, Quarry Creek Development, Marron Road, Carlsbad, California," prepared by 6Jl6 Geotechnical Solutions, Inc., Project No. Gl-19-11-155, dated June 25, 2020 PREVIOUS FIELD OBSERVATIONS As previously stated, 6M.6Geotechnical Solutions, Inc. had previously prepared a Report of As-Graded Geotechnical Engineering Observations and Compaction Testing for the project. In summary, our representative observed during rough grading the soil removals down to competent.soil material and soil recompaction of the building pad soils. For more detailed information on the work performed between April 11, 2023 through May 16, 2023, refer to our report dated June 10, 2023 (Revised August 11, 2025). FIELD OBSERVATIONS The following observations and soil testing during final grading were performed between June 10, 2023 and July 16, 2025. The earthwork was performed in accordance with the recommendations presented in our original report dated January 29, 2019 and additional supplementary documentation referenced herein. 1 . Our representative observed base placement and performed compaction for the main entry curb & Gutter and driveway approach. Observations and testing indicated at least 95% compaction levels as presented in memos issued to the contractor/ contractor's representative on July 16, 2025. 2. Our representative observed the bearing soils for the building, retaining wall and shade structure footings. The footing excavations were observed to be founded in suitable recompacted fill or dense formational soils. Footing trench observation memos were issued to the contractor/ contractor's representative on May 13, 2025, May 2, 2025, March 25, 2024, November 14, 2023, October 11, 2023 and October 9, 2023. Final Report of Grading Observations and Soil Testing August 18, 2025 Marron Road, Carlsbad (Project No. SDP2020-0005, Drawing No. 536-7 A) Page 3 3. Our representative was requested to observe the backfill placement for the sewer trench backfill, storm drain and manhole backfill, parking lot pavement subgrade over-excavation and recompaction. Wall backcuts mostly exposed native bedrock/ground and did not require major backfilling. Small wedge of backfill behind the wall consisted of¾" crushed rocks above the backdrainage system. Retaining walls perforated pipe backdrainage system was also observed by our representative( s ), however, waterproofing or sealing observations were beyond the scope of our work. Field memos summarizing field observations and compaction test results were issued to the contractor/ contractor's representative. 4. Other works not listed herein including final parking lot asphalt paving structural section subgrade/base/asphalt placement, the curb and gutter soil subgrade, remaining sitework improvements and wet and dry utility trench backfill observations and compaction testing were performed by another consultant. The testing consultant or laboratory should submit under a separate report the related engineering observations and testing results prepared by the responsible engineer in charge. SOIL TESTING Representative soil samples were collected during grading to determine laboratory maximum dry density of the soils per ASTM D1557, presented as Maximum Dry Density & Optimum Moisture Content List, Figure 2. Field density tests were performed at approximate locations shown on Figure 1, Approximate Compaction Test Location Map. The complete list of density test results are presented as Compaction Test Results, Figures 3 and 4. Equipment used for soil compaction included CAT DB Bulldozer and a CAT 963 Track, excavator and compaction wheel, track loader, wacker, Bobcat, drill rig (for shade structures foundations), depending on the operations being carried out. Water was added with a fire hose. Field density tests yielded a relative compaction of at least 90 percent or 95 percent, at tested locations, of the maximum laboratory dry density at the tested locations. Areas with failed tests were brought to the awareness of the grading contractor and recompacted until the recommended compaction was achieved. In general, the onsite soils used during grading consisted of clayey silty sand (SM-SC) deposits ranging to low expansion potential (Expansion Index less than 50 based on ASTM D4829 classification), as confirmed by additional expansion index (E.1.) testing of rough finish graded soils. Final Report of Grading Observations and Soil Testing August 18, 2025 Marron Road, Carlsbad (Project No. SDP2020-0005, Drawing No. 536-7A) Page 4 SITE SUITABILITY AND COMPLIANCE The observed and tested areas of the project site are, in our professional opinion, suitable for their intended use. The underlying Tonalite crystalline bedrock is suitable to support the recompacted fill for the new structures to be built and related exterior sitework improvements. We certify that the geotechnical engineering aspects of the grading reported herein are in compliance with the approved geotechnical report and approved grading plans. LIMITATIONS The findings and opinions presented herein have been made in accordance with currently accepted principles and practice in the field of geotechnical engineering in the City of Carlsbad. No warranty, either expressed or implied, is made. All statements in this grading report are applicable only for the grading operation observed and tested by our firm. The firm of 8ll8 Geotechnical Solutions, Inc. shall not be held responsible for fill soils placed without our observations and testing at any other time, or subsequent changes to the site by others, which directly or indirectly cause poor surface or subsurface drainage, water erosion, and/or alteration of the strength of the compacted fill soils. It is not within the scope of our services to provide quality control oversight for surface or subsurface drainage construction or retaining wall sealing and base of wall drain construction. It is the responsibility of the contractor(s) to verify proper wall sealing, geofabric installation, protection board installation (if needed), drain depth below interior floor or yard· surfaces, pipe percent slope to the outlet, etc. In the event that any changes in the nature, design, or location of the building or improvements are planned, the conclusions and recommendations contained in this report should not be considered valid unless the changes are reviewed and the conclusions of this report modified or verified in writing. Final Report of Grading Observations and Soil Testing August 18, 2025 Marron Road, Carlsbad (Project No. SDP2020-0005, Drawing No. 536-7A) Page 5 If you have any questions or need clarification, please contact this office at your convenience. Reference to our Project No. FC-23-04-124 will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. Respectfully submitted; 6Jf6Geotechnical Solutions, Inc. ·ncipal Engineer Attachments: Approximate Compaction Tests Location Map, Figure 1 Laboratory Maximum Dry Density & Optimum Moisture Content List, Figure 2 Compaction Test Results, Figures 3 and 4 Distribution: Addressee (3, email) 6.IISGeotechnical Solutions, Inc. Laboratory Maximum Dry Density & Optimum Moisture Content List (ASTM D1557) PROJECT NO: PROJECT NAME: LOCATION: REPORT DATED: Test Results: Soil Type (1 ): Maximum Dry Density: Optimum Moisture: FC-23-04-124 Children's Paradise Preschool Marron Road, Carlsbad August 18, 2025 Dark Brown Clayey Silty Sand 127.0 PCF 11.0% FIGURE 2 PROJECT NO: PROJECT NAME: PROJECT LOCATION: REPORT DATED: COMPACTION TEST RESUL_TS FC-23-04-124 Children's Paradise Preschool Marron Road, Carlsbad August 18, 2025 FIELD COMPACTION TEST RESULTS (ASTM D6938): Approximate Approximate Field Fleld Date Test No. Test Test Moisture Dry Soll Elevation (MSL) Density Type Location (ft) (%) (pcf) 04/13/2023 1 Pad Area 134'± 11.8 120.4 1 04/13/2023 2 Pad Area 134'± 12.4 119.7 1 04/13/2023 3 Pad Area 135.5'± 14.1 114.3 1 04/13/2023 4 Pad Area 136.5'± 11 .8 119.0 1 04/13/2023 5 Pad Area 137'± 12.2 120.0 1 04/13/2023 6 Pad Area 135.5'± 12.3 118.1 1 04/13/2023 7 Pad Area 136'± 11 .9 120.9 1 04/14/2023 8 Pad Area 138'± 12.1 118.6 1 04/14/2023 9 Pad Area 138'± 12.4 117.3 1 04/14/2023 10 Pad Area 138'± 13.0 114.5 1 04/25/2023 11 Pad Area 134'± 13.5 116.9 1 04/25/2023 12 Pad Area 134'± 13.6 118.1 1 04/26/2023 13 Pad Area 136'± 13.5 119.9 1 04/26/2023 14 Pad Area 136'± 13.2 120.0 1 04/27/2023 15 Pad Area 134'± 12.8 115.5 1 04/27/2023 16 Pad Area 134'± 11 .8 118.0 1 SJISGeotechnical Solutions, Inc. Max. Relative Dry Compaction Comments Density (Dcfl (%) 127.0 95 Bottom of Over-Ex@ 132.5'± 127.0 94 127.0 90 127.0 94 127.0 94 127.0 93 127.0 95 127.0 93 127.0 92 127.0 90 127.0 92 127.0 93 127.0 94 127.0 94 127.0 91 127.0 93 FIGURE 3 FIELD COMPACTION TEST RESULTS (ASTM D6938): Approximate Approximate Fleld Fleld Max. Relative Date Test No. Test Test Moisture Dry Soll Dry Compaction Comments Location Elevation (MSL) (ft) (%) Density Type Density (%) (pcf) (pcf.) 04/28/2023 17 Pad Area 136'± 11.2 119.1 1 127.0 94 04/28/2023 18 Pad Area 136'± 13.9 118.3 1 127.0 93 05/01/2023 19 Pad Area 138'± 12.9 117.0 1 127.0 92 05/01/2023 20 Pad Area 138'± 12.5 118.3 1 127.0 93 05/11/2023 21 Pad Area Rough Finish Grade 10.8 118.4 1 127.0 93 05/11/2023 22 Pad Area Rough Finish Grade 11.4 117.3 1 127.0 92 05/11/2023 23 Pad Area Rough Finish Grade 11.9 119.1 1 127.0 94 05/11/2023 24 Pad Area Rough Finish Grade 10.7 115.5 1 127.0 91 05/11/2023 25 Parking Lot Rough Finish Grade 13.5 120.7 1 127.0 95 Bottom of Over-Ex@ 136.5'± 05/15/2023 26 Trash Enclosure Rough Finish Grade 12.1 124.1 1 127.0 98 05/15/2023 27 Parking Lot Rough Finish Grade 12.9 123.0 1 127.0 97 05/16/2023 28 Parking Lot Rough Finish Grade 12.8 120.9 1 127.0 95 05/16/2023 29 Parking Lot Rough Finish Grade 12.0 123.1 1 127.0 97 06/08/2023 30 Storm Drain Trench Rough Finish Grade 10.9 116.9 1 127.0 92 06/08/2023 31 Storm Drain Trench Rough Finish Grade 11 .5 116.5 1 127.0 92 07/17/2023 32 Sewer Trench Rough Finish Grade 11.0 118.0 1 127.0 93 07/17/2023 33 Sewer Trench Rough Finish Grade 12.0 118.9 1 127.0 94 07/17/2023 34 Sewer Trench Rough Finish Grade 10.4 116.7 1 127.0 92 07/16/2025 35 Curb & Gutter, Finish Base Grade 11 .5 113.8 2 119.0 96 Driveway Approach 07/16/2025 36 Driveway Approach Finish Base Grade 10.8 113.1 2 119.0 95 6.IILGeote<thnical Solutions, Inc. FIGURE 4 GEOTECHNICAL LEGEND A pprox. Limits of G rading/ t:om p acted F Iiis Approx. Compaction Test: Locet:l on 1FHI / Tonalite (Bedrock) o . : FC-23-04-124 rt of Grading Ot'J ---bated:: ausi 202s ., ,-- ··-·:~~-~: :;:_:;;;~~==·--~ \ 1 .--• ---,o • --·--I I ' .. .. ACTION TESTS LOCATION M l SCALE 1"=50' ----------r----- E------19 4r .. . .>0. ·.j ! -~---.--'---.,i . : \ ,••· = '· /ft~ I, -IMU t>-.J I.JOO 0.:, IP,11 IJIS.00 ·-c-, ll5.17 1.HJIII , .. 1118 O#}IMU c-, ,.a.,o , .... ., 1'477 --. t>-.J 141.4.J 1.1&70 1,17,.., t>-.J , .. .., ,.-,o , .. ,o t?oGIMU 0.:, H IJU4 ll.UO U7.50 l[lal/lMU c-, 14'.li ll&OO IJ7,,0 O-;J 141.li IJll.QO I.J:l.<.t 0.:, IG.lf uuo ,.a,7 rM>IWL O-;J 141.87 141.$11 ·-IIElallWL 0-2 141.87 IAIIO IP,00 C-2 141.D ., . .,., _,,, 0-1 ,a. .. ,_ l;Jf.31 0-2 142.H , .. ,,, ..... EMI IIMU. C-1 14.UI u,.,o IJUII --14.ff I.JUI , .. ,., ,a.a 140.10 , .. ., l<UII ffG.10 IJUII ,_ 141UO 1.JUO ·-f,O.,O IJUII EMIIIMU. loH.71 , ... ,. 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