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Home My WebLink AboutPD 2020-0036; PLAZA BONITA SLOPE REPAIR; FINAL SOILS REPORT; 2021-04-07B&B Engineering, Inc. CIVIL, GEOfECHNICAL, & QUALITY ENGINEERING FOUNDATION DESIGN* LAND SURVEYING * son, TESTING CLIENT: LA COSTA, HOA PROJECT: LAC 720-SLOPE DATE: 7 APRIL 2021 LA COSTA VILLAGE, HOA 2210 Plaza Bonita Carlsbad, CA. 92009 Attention: R.J. Barberio FINAL SOIL REPORT Subject: Geotechnical Acceptance of Compaction for the Slope Repair located at 2210 Plaza Bonita, Carlsbad, CA. (City Project No: GR 2020-0026) (APN: 215-232-20-36) Reference (a): Geotechnical Inspection of Slope Failure Report by Martin R. Owen, PE, GE dated June 1, 2020 Reference (b): Slope Repair Grading Plans by Robert 0. Sukup, PE 28302 dated 12/28/2020 Gentlemen: Pursuant to your request and authorization, we have completed our inspection and compaction testing of the re-grading operations for the subject slope repair at the subj ect site. Locations of our field density tests are shown on Enclosure (1), and the results of these soil tests are detailed on Enclosure (2). Site preparation, compaction, and testing were accomplished between September 21, 2020 and March 17, 2021. Based on our observations and testing, it is our opinion that the work performed during that p,eriod was in general conformance with Reference (a), the Approved Grading Plans and the requirements of the City of Carlsbad Grading Ordinance. SITE GRADING On September 21, 2020, clearing began on the subject site with the contractor removing some shrubs and other surface vegetation. All debris was removed from the grading area. On this date, the contractor, Mike Lloyd Excavating, Inc., began the excavation operation for the supporting shear key by removing the· native soils along the toe of the proposed fill slope. The bottom of the excavation was scarified, watered as necessary, and re-compacted prior to replacing the stockpiled soil. On September 24, 2020, the contractor had to stop all grading operations at this site until a Grading Permit could be obtained from the City of Carlsbad. On March 8, 2021, grading for the slope repair continued subsequent to obtaining a grading permit. The contractor continued the grading operation along the toe of the slope by re- excavating the loose, wet soil in the slope key to a depth of 2 feet. The contractor placed a mixture of the wet soils on-site and the dryer stockpiled material. Fill was placed and compacted in thin lifts ( +/ -6"). . On March 5 ,-2021, the contractor placed the 1 ST layer of Geogrid soil reinforcement matena~ on a level berich in the slope at an elevation of 2' above the toe of slope. All density . . . . . 1611-A so. MELROSE DRIVE #285, VISTA, CA eio81-5471 Ph: (760} 945-3150 Fax: (760} 726-7514 . ~ B&B Engineering, Inc. tests performed during the slope re-grading operation are measured from the toe of the fill slop~ where the soil met the top of the pool deck. The contractor continued benching into the native slope soil materials and the Landslide deposits and mixing with the stockpile soils. The soil mix was then placed in thin lifts, watered as necessary, and compacted to achieve the required 90% relative compaction. On March 8, the 2ND layer of geogrid was placed in the slope at an elevation of 6' above the toe of slope. The 3 RD and 4TH layers of Geo grid material were placed at elevations of l O feet and 14 feet above the toe of slope, respectively. The contractor placed and compacted the native soils mix on the slope until the designed grades were achieved. Density of the fill material was achieved by the use of a hand whacker and a walk-along vibrating steel wh~el sheepsfoot roller compacting the soil as fill was placed in thin lifts. The fill soils have been moisture conditioned to near optimum moisture content prior and during fill placement and compaction. Based on our inspections and soil testing during the slope re-grading operation,.it is our opinion that the subject reinforced slope repair is in conformance with the recommendations and requirements of References (a) and (b) and the City of Carlsbad Grading Ordinance. The Engineer has prepared this Report for the exclusive use of the client and authorized agents. This Report has been prepared in accordance with generally accepted soil and foundation engineering practices. No other warranties, either expressed or implied, are made as to the professional advice provided under the terms of this agreement, and included in the Report. B & B Engineering Inc. appreciates this opportunity to be of service. Should you have any questions regarding this project, please do not hesitate to contact us. Sincerely, iv Stephen B. Peter RCE 38623 Expires 3-31-23 ~~,e~ Dennis P Beard PLS President -2- 1611-A SO. MELROSE DRIVE#285, VISTA, CA 92081-5471 Ph: (760) 945-3150 Fax: (760) 726-7514 18. APPROXIMATE LOCATION OF FIELD DENSITY TEST PLOT PLAN Owner: LA COSTA VILLAGE SITE 2210 PLAZA BONITA Address CARLSBAD.CA ~ B&B Engineering~ Inc A.P.N.: 215-232-20-36 Project: LA COST A VILLAGE Date: 4/6/2021 ENCLOSURE ( 1 -~ B&B Engineering~ Inc -Client LA COSTA VILLAGE Project LAC 720-SLOPE Date: 4/6/2021 Test Test Soil Ory Density, pcf Moisture,% Relative Retest No. Test Date Test Location E1/0epth Tvoe FIeIa Maximum r-18I0 upt. .... ompact1on NO. 1 9/22/20 KEY BACKFILL -2 A 97.1 105.0 29.7 16.5 92 2 9/22/20 KEY BACKFILL -2 A 101.4 105.0 17.9 16.5 97 3 9/23/20 TOE OF SLOPE O' A 96.8 105.0 24.2 16.5 92 4 9/23/20 TOE OF SLOPE O' A 98.4 105.0 23.7 16.5 94 5 9/24/21 TOE OF SLOPE 1' A 94.9 105.0 10.5 16.5 90 6 3/4/21 FILL SLOPE 3' A 95.2 105.0 23.7 16.5 91 7 3/4/21 FILL SLOPE 3' A 96.4 105.0 26.1 16.5 92 8 3/5/21 FILL SLOPE 4' A 98.1 105.0 29.5 16.5 93 9 3/5/21 FILL SLOPE 4' A 97.4 105.0 22.7 16.5 93 10 3/5/21 FILL SLOPE 5' A 95.1 105.0 26.4 16.5 91 . 11 3/8/21 FILL SLOPE 5' A 101.4 105.0 19.5 16.5 97 12 3/8/21 FILL SLOPE 6' A 97.5 105.0 21 .8 16.5 93 13 3/9/21 FILL SLOPE 8' A 99.3 105.0 20.6 16.5 95 14 3/9/21 FILL SLOPE 9' A 98.0 105.0 20.5 16.5 93 15 3/9/21 FILL SLOPE 10' A 100.0 105.0 19.6 16.5 95 16 3/15/21 FILL SLOPE 11' A 98.0 105.0 19.0 16.5 93 17 3/16/21 FILL SLOPE 12' A 98.2 105.0 20.5 16.5 94 18 3/17/21 FILL SLOPE 14' A 96.6 105.0 18.8 16.5 92 NOTE: DENSITY TESTS MEASURED FROM TOE OF SLOPE COMPACTION CURVE DATA OPTIMUM MAXIMUM DRY SOIL TYPE AND DESCRIPTION MOISTURE% DENSITY lncf\ A -DARK GREY SIL TY CLAY 16.5 105.0 COMPACTION TEST DATA ENCLOSURE (2)