HomeMy WebLinkAboutCUP 2018-0023; BUENA VISTA RESERVOIR SITE (PARK) ONSITE; FINAL SOILS REPORT; 2021-08-20FINAL REPORT OF TESTING
AND OBSERVATION SERVICES
PERFORMED DURING ONSITE
IMPROVEMENTS
BUENA VISTA RESERVOIR SITE
(PARK)
CARLSBAD, CALIFORNIA
PREPARED FOR
AUGUST 20, 2021
PROJECT NO. G2225-52-03
Project No. G2225-52-03
August 20, 2021
Lennar Homes of California, Inc.
15131 Alton Parkway, Suite 365
Irvine, California 92618
Attention: Ms. Lisa Galloway
Subject: FINAL REPORT OF TESTING AND OBSERVATION
SERVICES PERFORMED DURING ONSITE IMPROVEMENTS
BUENA VISTA RESERVOIR SITE (PARK)
CARLSBAD, CALIFORNIA
Dear Ms. Galloway:
In accordance with your request, we prepared this final report of our testing and observation services
for the offsite improvements for the Buena Vista Reservoir Park site in Carlsbad, California. We
provided compaction testing and observation services on an “on call” basis, as requested by the site
superintendent during construction of on-site improvements. We performed our services during the
period of February 11 through June 29, 2021.
The scope of our services included:
Performing in-place density tests on an “on-call” basis for utility trench backfill operations for
storm drain and water main.
Performing in-place density tests for sidewalk subgrade soil for pedestrian and maintenance
vehicle pathways and for subgrade soil below the resilient surface area of the playground. We
also performed in-place density tests during placement of aggregate base below the resilient
surface area of the playground.
Observing the construction of the new biofiltration basin in the northwest corner of the site,
including the installation of the impermeable liner, gravel storage layer, filter sand/stone layer,
and amended soil layer.
Providing geotechnical consultation services during improvement operations.
Performing laboratory tests to aid in evaluating the compaction characteristics of soil conditions
encountered and/or used for fill including base materials
Preparing this final report of improvements.
GEOCON
INCORPORATED
GEOTECHNICAL ■ ENVIRONMENTAL ■ MATE RI ALS O
6960 Flanders Drive ■ San Diego, California 92121-297 4 ■ Telephone 858.558.6900 ■ Fax 858.558.6159
Geocon Project No. G2225-52-03 - 2 - August 20, 2021
To aid in preparing this report, we reviewed the following report and plans associated with the project
improvements:
1.Final Report of Testing and Observation Services Performed During Site Grading, Buena
Vista Reservoir Site (Park), Carlsbad, California, prepared by Geocon Incorporated, dated
July 27, 2021 (Project No. G2225-52-03).
2.Improvement Plans for: Buena Vista Reservoir Site (Park), Carlsbad, California prepared by
City of Carlsbad Engineering Department, dated September 10, 2020. (Drawing No.521-1,
Project NO. CUP 2018-0023)
We observed the construction of the new biofiltration basin at the northwest corner of the site. The
bottom of basin was founded in dense formational materials. We observed the installation of the
impermeable liner, and we observed that the gravel storage layer, filter sand/stone layer, and amended
soil layer were installed to the depths indicated on the project plans.
During the construction of site improvements, we observed compaction procedures and performed in-
place density tests to evaluate the dry density and moisture content of the fill materials. We performed
in-place density tests using a nuclear gauge in accordance with ASTM Test Procedure D 6938. Table I
presents the results of the in-place density tests. We used the referenced plans in the field to identify
in-place density test locations for the utility and surface improvement areas.
We performed laboratory tests on soil samples in accordance with ASTM Test Procedures D 1557,
Maximum Dry Density/Optimum Moisture Content. Table II presents the results of the laboratory
tests.
The results of the in-place density tests indicate that the utility trench backfill, pedestrian use sidewalk
subgrade, and subgrade for playground resilient turf possess a dry density of at least 90 percent of the
laboratory maximum dry density near to slightly above the optimum moisture content at the locations
tested. In-place density test results indicate that vehicular use sidewalk subgrade and base material for
the playground resilient turf possesses a dry density of at least 95 percent of the laboratory maximum
dry density near to slightly above the optimum moisture content at the locations tested.
Based on our observations and test results, we opine the construction of site improvements, which is
the subject of this report, has been performed in substantial conformance with the recommendations of
the project geotechnical report. Additional improvement installation performed at the site should be
accomplished in conjunction with our observation and testing services. This office should be notified
at least 48 hours prior to commencing additional grading or backfill operations.
Adequate drainage provisions are imperative. Under no circumstances should water be allowed to
pond adjacent to improvements. Finish grades should be established so that drainage water is directed
Geocon Project No. G2225-52-03 - 3 - August 20, 2021
Project Name:Project No.:Pre. No. Re.B 1 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 135.9 7 95 95B 2 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 135.6 7.1 95 95B 3 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 136.1 6.8 95 95B 4 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 136.4 5.9 95 95B 5 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 135.8 5.5 95 95B 6 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 137.1 6.3 96 95B 7 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 136.2 6.1 95 95B 8 6/4/21 Resilient Playground Surfacing Area B 4 0 143.3 6.1 136.8 5.1 95 95Required Relative Compaction (%)Relative Compaction (%)Test No. Date (MM/DD/YY)LocationElev. or Depth (feet)Curve No.>¾" Rock (%)Max. Dry Density (pcf)Opt. Moist Content (%)Field Dry Density (pcf)Field Moisture Content (%)TABLE ISUMMARY OF FIELD DENSITY TEST RESULTSBuena Vista Reservoir Park On-SiteG2225-52-03OGEOCON
Project Name:Project No.:Pre. No. Re.SD 1 02/11/21 SD Line Running SE to NW -1 3 0129.0 9.7 118.7 8.9 92 90SD 2 02/11/21 SD Line Running SE to NW -4 3 0129.0 9.7 116.8 8.7 91 90SD 3 02/11/21 SD Line Running SE to NW -4 3 0129.0 9.7 115.9 8.7 90 90SD 4 02/11/21 SD Line Running SE to NW -3 3 0129.0 9.7 117.9 8.9 91 90SD 5 02/11/21 SD Line Running SE to NW -2 3 0129.0 9.7 122.2 9.1 95 90SD 6 02/11/21 SD Line Running SE to NW -1 3 0129.0 9.7 119.4 8.7 93 90SD 7 02/11/21 SD Line from Playground to SW -1 3 0 129.0 9.7 117 8.7 91 90SD 8 02/11/21 SD Line from Playground to SW -1 3 0 129.0 9.7 117.6 8.7 91 90Required Relative Compaction (%)Relative Compaction (%)Test No. Date (MM/DD/YY)LocationElev. or Depth (feet)Curve No.>¾" Rock (%)Max. Dry Density (pcf)Opt. Moist Content (%)Field Dry Density (pcf)Field Moisture Content (%)TABLE ISUMMARY OF FIELD DENSITY TEST RESULTSBuena Vista Reservoir Park On-SiteG2225-52-03OGEOCON
Project Name:Project No.:Pre. No. Re.SG 1 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 122.3 10.5 95 90SG 2 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 122.7 10.1 95 90SG 3 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 124.1 8.9 96 90SG 4 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 122.3 10.5 95 90SG 5 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 123.9 9.1 96 90SG 6 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 122.5 9.6 95 90SG 7 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 122.1 10 95 90SG 8 6/3/21 Resilient Playground Surfacing Area 0 3 0 129.0 9.7 123.7 10.9 96 90Required Relative Compaction (%)Relative Compaction (%)Test No. Date (MM/DD/YY)LocationElev. or Depth (feet)Curve No.>¾" Rock (%)Max. Dry Density (pcf)Opt. Moist Content (%)Field Dry Density (pcf)Field Moisture Content (%)TABLE ISUMMARY OF FIELD DENSITY TEST RESULTSBuena Vista Reservoir Park On-SiteG2225-52-03OGEOCON
Project Name:Project No.:Pre. No. Re.SW 1 2/22/21 0 2 0 135.4 7.9 132.9 7.1 98 95SW 2 2/22/21 0 2 0 135.4 7.9 129.9 6.9 96 95SW 3 2/22/21 0 2 0 135.4 7.9 132.6 6.9 98 95SW 4 2/22/21 0 2 0 135.4 7.9 128.7 6.9 95 95SW 5 2/22/21 0 2 0 135.4 7.9 130.3 6.9 96 90SW 6 2/26/21 0 3 0 129.0 9.7 125.5 8.7 97 95SW 7 2/26/21 0 2 0 135.4 7.9 130.2 6.9 96 95SW 8 2/26/21 0 2 0 135.4 7.9 131.2 6.9 97 95SW 9 2/26/21 0 2 0 135.4 7.9 129.6 6.9 96 95SW 10 2/26/21 0 2 0 135.4 7.9 130.3 7.1 96 95SW 11 5/18/21 0 2 0 135.4 7.9 128.9 6.9 95 90SW 12 5/18/21 0 2 0 135.4 7.9 127.5 7.1 94 90SW 13 5/18/21 0 2 0 135.4 7.9 125.8 6.9 93 90SW 14 6/29/21 0 3 0 129.0 9.7 119.4 10.2 93 90Western DG PathWestern DG PathWestern DG PathPedestrian Flatwork NE of PlaygroundPerimeter Vehicular Sidewalk - EPerimeter Vehicular Sidewalk - EPerimeter Vehicular Sidewalk - SPerimeter Vehicular Sidewalk - SWPerimeter Vehicular Sidewalk - WPerimeter Vehicular Sidewalk - NWPerimeter Vehicular Sidewalk - NWPerimeter Vehicular Sidewalk - NWPerimeter Vehicular Sidewalk - WPedestrian Sidewalk Stairs - SRequired Relative Compaction (%)Relative Compaction (%)Test No. Date (MM/DD/YY)LocationElev. or Depth (feet)Curve No.>¾" Rock (%)Max. Dry Density (pcf)Opt. Moist Content (%)Field Dry Density (pcf)Field Moisture Content (%)TABLE ISUMMARY OF FIELD DENSITY TEST RESULTSBuena Vista Reservoir Park On-SiteG2225-52-03OGEOCON
Project Name:Project No.:Pre. No. Re.WM 1 4/21/21 Water Tie-in NE Area of Site 178 2 0 135.4 7.9 122.9 8.5 91 90WM 2 4/21/21 Water Tie-in NE Area of Site 180 2 0 135.4 7.9 123.5 8 91 90WM 3 4/21/21 Water Tie-in NE Area of Site 182 2 0 135.4 7.9 121.9 8.8 90 90Required Relative Compaction (%)Relative Compaction (%)Test No. Date (MM/DD/YY)LocationElev. or Depth (feet)Curve No.>¾" Rock (%)Max. Dry Density (pcf)Opt. Moist Content (%)Field Dry Density (pcf)Field Moisture Content (%)TABLE ISUMMARY OF FIELD DENSITY TEST RESULTSBuena Vista Reservoir Park On-SiteG2225-52-03OGEOCON
Project Name:Buena Vista Reservoir Park On-Site Project No.: G2225-52-03AC Asphalt Concrete IT Irrigation Trench SG SubgradeAD Area Drain JT Joint Trench SL Sewer LateralBBaseM Moisture Test SM Sewer MainCG Curb/Gutter MG Minor Grading SR Slope RepairDW Driveway MSE Mechanically Stabilized Earth Wall ST Slope TestET Electrical Trench PT Plumbing TrenchSW SidewalkETB Exploratory Trench RGRegradeSZ Slope ZoneFB Footing Backfill RWL Reclaimed Water Lateral UT Utility TrenchFG Finish Grade RWM Reclaimed Water Main WB Wall BackfillFS Fire Service SBTSubdrain TrenchWL Water LateralGT Gas Trench SDStorm DrainWM Water MainA, B, C, …R*SC Denotes Sandcone Density TestCorresponds to the elevation or the depth, in feet, of the in-place density/moisture content test. The value has been rounded to the nearest whole foot. CURVE NO.Corresponds to the curve numbers presented in the summary of the laboratory maximum dry density and optimum moisture content test results. The field representative selected the curve no. based on the laboratory test results and field observations.>¾" ROCK - ROCK CORRECTIONThe laboratory maximum dry density and optimum moisture content can be adjusted for in-place soil that possesses rock larger than ¾ inch. The curve no. is adjusted for the percentage of ¾ inch rock in accordance with ASTM D 4718 or Woodward Clyde guidelines.Fill in area of density test was removed during construction operationsELEVATION OR DEPTHTABLE ISUMMARY OF FIELD DENSITY TEST RESULTSTEST NO. - PREFIXTEST NO. - RE.Retest of previous density test failure following additional moisture conditioning or recompaction0GEOCON
Geocon Project No. G2225-52-03 August 20, 2021
TABLE II
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND
OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557
Sample No. Description
Maximum
Dry
Density
(pcf)
Optimum
Moisture
Content
(% dry wt.)
2 Reddish brown, Silty fine SAND; trace gravel 135.4 7.9
3 Reddish brown, Silty fine SAND 129.0 9.7
4 Gray, fine to coarse Sandy GRAVEL; trace silt 143.3 6.1