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Home My WebLink AboutCDP 16-27; TABATA RANCH LOT 3; INTERIM AS-GRADED GEOTECHNICAL REPORT PROPOSED TABATA RANCH SUBDIVISION; 2015-08-02CTf1 Construction Testing & Engineering, Inc. Inspection I Testing I Geotechnical I Environmental & Const,uclion Engineering I CM Engineering'Surveying INTERIM AS-GRADED GEOTECHNICAL REPORT PROPOSED TABATA RANCH SUBDIVISION LEMON LEAF DRIVE CARLSBAD, CALIFORNIA PREPARED FOR: TABATA FAMILY TRUST C/O: GREGG HARRINGTON P.O. BOX 943 CARLSBAD, CALIFORNIA I • • . DEC 05 2016 I Y - . t. . •••,... PREPARED BY: CONSTRUCTION TESTING & ENGINEERING, INC. 1441 MONTIEL ROAD, SUITE 115 ESCONDIDO, CALIFORNIA 92026 CTE PROJECT NO. 10-12101G JULY 6, 2015, MODIFIED AUGUST 2, 2015 1441 Montiel Road, Suite 115 1 Escondido, CA 92026 1 Ph (760) 746-4955 1 Fax (760) 746-9806 1 www.cte-lnc.net TABLE OF CONTENTS SECTION PAGE 1.0 BACKGROUND .......................................................................................................................1 2.0 PROJECT INFORMATION......................................................................................................2 3.0 FILL PLACEMENT .................................................................................................................. 3 4.0 TESTING ................................................................................................................................... 3 5.0 ADDITIONAL CONSTRUCTION OBSERVATION ............................................................... 4 6.0 CONCLUSIONS AND RECOMMENDATIONS ....................................................................4 7.0 LIMITATIONS ............................................................................................................. . ............. 5 TABLES TABLE I TABLE II FIGURES FIGURE 1 FIGURE 2 COMPACTION TEST SUMMARY LABORATORY TEST DATA SITE INDEX MAP COMPACTION TEST LOCATION MAP \\Esc_serveiprojects\10-1210IGRpt_Intenn Comp 10-12101 [07-06-2015].doc Interim As-Graded Geotechnical Report Page 1 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTE Job No. 10-12101G 1.0 BACKGROUND This document provides information regarding testing of compacted fill for the grading operations completed in 2014 at the proposed Tabata Ranch Subdivision located on Lemon Leaf Drive in Carlsbad, California. Our work was authorized through CTE proposal no. G-3191, dated June 1, 2014. Part of the site was previously graded (Lots 1 and 2) based on the preliminary geotechnical investigation performed by Vinje & Middleton Engineering, Inc. (Job No. 01-364-P) dated August 2, 2006. Grading procedures and testing of compacted fill for these lots was conducted by Vinje & Middleton Engineering, Inc. personnel. CTE reviewed field grading observation reports from the testing and observations of these lots, in addition to performing surface testing on these two lots, with adequate compaction test results. CTE also reviewed the previously prepared geotechnical report and was in general agreement with the data, conclusions, and recommendations. Based on the previously performed limited investigation, the site had Quaternary Previously Placed Fill soils overlying sedimentary bedrock units of the Eocene Age. Fill soils were generally found to a maximum depth of 5.5 feet below existing grades. The attached Figure 1 shows the approximate location of the site and surrounding area. \\Esc_serveT\projects\1O-121O1GRpt_Interm Comp 10-12101 [07-06-2015].doc Interim As-Graded Geotechnical Report Page 2 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTE Job No. 10-12101G 2.0 PROJECT INFORMATION This report includes a summary of test results and observations performed by CTE during the recent (2014) placement of compacted fill for the proposed building pads and associated improvements. Conditions encountered at the site were found to consist of previously placed fill and residual soils overlying sedimentary bedrock. Previously placed fill and other disturbed near surface soils were generally found to consist of loose, silty sand. These materials were removed beneath improvement areas prior to placement of compacted fill as part of the recent grading operations. As indicated, loose and disturbed surface soils and previously placed fill were excavated to between elevations 253 feet above mean seal level (msl) and 272 msl, depending on location. The exposed bottoms of excavations were observed, tested, and confirmed (as appropriate) prior to placement of the compacted fill. Exposed areas to receive fill were then scarified, moisture conditioned, and compacted in general accordance with project requirements. Following subgrade preparation, fill materials were moisture conditioned, placed in thin uniform lifts, and then compacted. Excavations and compaction within the improvement areas were conducted with a D8 bulldozer and a 980 rubber-tired front loader. Mountain Movers was the grading contractor for the project. Additional grading throughout the subject site consisted of parking and drive areas, minor excavations, wall backfill, and utility installation. Minor grading and compaction testing for utility tie-ins conducted in the adjacent Lonicera Street right-of-way is also documented herein. \\Esc_servetprojects\10-12101G\Rpt_Intenn Comp 10-12101 [07-06-2015].doc Interim As-Graded Geotechnical Report Page 3 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTEJob No. 10-12101G 3.0 FILL PLACEMENT Fill soils consisting of onsite stock piled materials were generally placed in uniformly compacted lifts at above optimum moisture content. Compaction was performed to the appropriate minimum values (90% for building pad areas and 95% for pavement subgrade areas), as determined by ASTM D1557. Grading was performed using standard construction equipment, followed by mixing, moisture conditioning, and compaction procedures. Backfill placement and compaction were performed in overall conformance with the project geotechnical recommendations. 4.0 TESTING Testing was performed to supplement field observations. Testing of compacted fill addressed by this report was conducted, as scheduled by the contractor, between July 1, 2014 and November 10, 2014. Field-testing of the compacted fill soil was conducted in accordance with ASTM D-6938-08a (nuclear method). Results of the field-testing indicate that fill materials were compacted to at least 90 percent or 95 percent (depending on location) of the laboratory maximum dry density, as required, in accordance with ASTM D 1557. Fill material was generally compacted at above optimum moisture content. Tabulated results of the field compaction testing are provided in the attached Table I, "Compaction Test Summary." Laboratory determination of the reference compaction values for the fill materials is provided in Table II, "Laboratory Test Results." Figure 2 shows the approximate location of the compaction tests performed, as well as other pertinent as-graded information. \Esc_server\projects\I0-12I01G\RptInterm Comp 10-12101 [07.06-2015].doc Interim As-Graded Geotechnical Report Page 4 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTE Job No. 10-12101G Based on site observations and laboratory testing, it appears the expansion potential for onsite materials is generally very low (Expansion Index < 20). 5.0 ADDITIONAL CONSTRUCTION OBSERVATION CTE observed subsurface water seepage along the dense formation contact during the overexcavation of the lower building pad (proposed elevation 276.0 feet) of Lot 3. Based on our observations and discussions, the installation of a subdrain, which consisted of a typical minimum four-inch diameter perforated pipe, surrounded by 3/4-inch rock/gravel, and surrounded by filter fabric, was installed and connected to the south end of the adjacent retaining wall backdrain. The subdrain extended along the entire Lot 3 toe of slope that connects the upper and lower building pads. Additional grading and backfilling, if any, should be observed and tested by CTE. In addition, prior to any significant future development, an appropriate update geotechnical investigation and report should be completed. 6.0 CONCLUSIONS AND RECOMMENDATIONS CTE concludes that the soil engineering and engineering geologic aspects of the grading covered by this report are in compliance with the approved geotechnical report and the grading plans (City of Carlsbad Drawing No. 471-9A, Assessors Parcel Numbers APN: 214-631-20 & 214-630-20). However, we understand that the site structures are not proposed for construction at this time. Therefore, prior to commencing with future construction, CTE should review the final proposed structural locations and details in order to provide update recommendation for building pad \\Esc_servei\projccts\10-12101G\Rpt_Interm Comp 10-12101 [07-06-2015].doc Interim As-Graded Geotechnical Report Page 5 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTE Job No. 10-12101G overexcavations, as appropriate. Due to the passing of time since building pad preparations, at a minimum, surficial remediation should be anticipated prior to recommencing building construction. Any vegetation, debris, or any other loose or dry material should be removed and replaced by compacted backfill to the required subgrade elevations, as necessary. As such, we anticipate (at a minimum) it will be appropriate to remove any vegetation and then scarify, moisture condition, and recompact the top six to 12 inches of building pad subgrade soils. However, CTE should confirm the adequacy of the building pad and surrounding areas during construction. CTE should also observe and confirm all footing excavations, as they are performed, in order to confirm adequate conditions. 7.0 LIMITATIONS As limited by the scope of the services that CTE agreed to perform, opinions presented herein are based on observations, test results, and understanding of the proposed site development. CTh's service was performed according to the currently accepted standard of practice by reputable consultants. No warranty, express or implied, is given or intended with respect to the performance of the project in any respect. Submittal of this report should not be construed as relieving the grading contractor of his responsibility to comply with the project requirements. The opportunity to be of service is appreciated. If you have any questions regarding testing conducted, observations made during construction or recommendations presented herein, please do not hesitate to contact this office. \Esc_scrver\projects\10-12I01G\Rpt_1nterm Comp 10-12101 [07-06-2015].doc Interim As-Graded Geotechnical Report Page 6 Proposed Tabata Ranch Subdivision Lemon Leaf Drive, Carlsbad California July 6, 2015, Modified August 2, 2015 CTE Job No. 10-12101G Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. Dan T. Math, GE #2665 No.2665 Principal Engineer \EXP12/31/I6)$ RJJ/DTM:nri \\Esc_server\projccts\10-12101G\Rpt_Intcrm Conip 10-12101 [07-06-2015].doc TABLE I COMPACTION TEST SUMMARY Job Name: Tabata Ranch Job Address: - Lemon Leaf Drive, Carlsbad Job No. 10-12101G Date: 07/06/02015 Date Test No. Location Elevation or Depth Feet Density pcf Moisture Content .%Dry Weight Relative Compaction % Soil Type 7/1/2014 1 Strawberry Place/Street 254.0 114.8 1 9.8 91% -- 7/1/2014 2 Strawberry Place/Street 256.0 115.2 10.3 92% 7/1/2014 3 Strawberry Place/Street 256.0 - 14.1 10.5 91% 1_ 7/1/2014 4 Strawberry Place/Street 258.0 - 13.7 10.9 90% 1 - 7/1/2014 5 Strawberry Place/Street 260.0 112.5 11.9 91% 2 7/1/2014 6 Strawberry Place/Street 260.0 14.0 - 12.3 92% 2 7/2/2014 7 Strawberry Place/Street 258.0 114.7 12.8 92% 2 7/2/2014 8 Strawberry Place/Street 262.0 13.3 - 12.6 91% 2 7/2/2014 9 Strawberry Place/Street 262.0 15.1 - 12.2 1 93% 2 7/2/2014 10 Strawberry Place/Street 264.0 115.9 11.4 93% 2 7/2/2014 11 Strawberry Place/Street 264.0 113.8 11.8 92% 2 7/2/2014 12 Strawberry Place/Street 263.0 116.4 12.7 94% 2 7/2/2014 13 Strawberry Place/Street 265.0 114.5 12.0 92% 2 7/2/2014 14 Strawberry Place/Street 265.0 115.0 12.3 93% 2 7/2/2014 15 Strawberry Place/Street 263.0 113.9 11.1 92% 2 7/2/2014 16 Strawberry Place/Street 267.0 113.8 11.5 92% 2 7/2/2014 17 Strawberry Place/Street 267.0 116.0 12.4 93% 2 7/2/2014 18 Strawberry Place/Street 265.0 115.7 12.0 93% 2 7/3/2014 19 Strawberry Place/Street 269.0 114.2 12.4 - 92% 2 7/3/2014 20 Strawberry Place/Street 269.0 113.7 1.6 - 91% 2 7/3/2014 21 Strawberry Place/Street 264.0 _11_ 1.8 - 96% 2 7/3/2014 22 Strawberry Place/Street 266.0 _117_ 12.6 94% 2 7/7/2014 23 Strawberry Place/Street 266.0 _11_ 12.2 94% 2 7/7/2014 24 Strawberry Place/Street 266.0 _115_ 12.0 93% 2 7/7/2014 25 Strawberry Place/Street 268.0 118.2 11.7 95% 2 7/7/2014 26 Strawberry Place/Street 268.0 118.5 12.0 95% 2 7/7/2014 27 Strawberry Place/Street 270.0 _116.6 12.4 94% 2 7/7/2014 28 Strawberry Place/Street 270.0 _115.9 13.3 93% F- 7/8/2014 29 Lot Fill Slope 265.0 _110.0 15.1 95% 3 7/8/2014 30 Lot Fill Slope 267.0 111.2 15.7 97% 3 7/8/2014 31 Lot Fill Slope 267.0 _11_ 14.9 97% 3 7/8/2014 32 Lot Fill Slope 269.0 110.3 15.9 96% 3 7/8/2014 33 Lot Fill Slope 269.0 109.4 13.6 95% 3 7/8/2014 34 Lot 5 Fill Slope 271.0 105.7 13.5 92% 3 7/812014 35 Lot 5 Fill Slope 271.0 108.0 14.4 94% 3 7/8/2014 36 Lot 5 Fill Slope 271.0 109.1 14.0 95% 3 7/8/2014 37 Strawberry Place/Street 271.0 108.6 14.5 94% 3 7/8/2014 38 Strawberry Place/Street 271.0 _110.7 _152 96% 3 7/9/2014 39 Lot 273.0 113.4 3.5 - 98% 3 7/9/2014 40 Lot 273.0 110.1 3.8 - 96% 3 7/9/2014 41 Lot 273.0 _112.4 3.6 - 98% 3 7/9/2014 42 Lot 4 274.0 110.3 2.9 - 96% 3 7/9/2014 43 Lot 274.0 109.3 13.2 95% 3 7/9/2014 44 Lot 274.0 111.8 13.7 97% 3 7/9/2014 45 Lot 5 273.0 112.0 14.2 97% 3 7/9/2014 46 Lot 5 273.0 109.5 14.8 95% 3 7/10/2014 47 Lot 3/Upper Pad 284.0 105.3 15.1 91% 3 FAILED, SEE RETEST TABLE I COMPACTION TEST SUMMARY Job Name: Tabata Ranch Job Address: Lemon Leaf Drive, Carlsbad - Job No. 10-12101G Date: 07/06/02015 Date Test No. Location Elevation or Depth Feet Density pcf MoiSture Content %Diy Weight Relative Compaction % Soil Type 7/10/2014 48 Lot 3/Upper Pad 285.0 106.6 1 15.3 93% 3 7/10/2014 49 Lot 3/Upper Pad 284.0 107.0 15.0 93% 3 7/10/2014 50 Lot 3/UpperPad 285.0 105.1 15.5 91% 3 7/10/2014 51 Lot 273.0 108.4 14.2 94% 3 7/10/2014 52 Lot 273.0 111.3 14.0 97% 3 7/10/2014 53 Lot 273.0 112.0 14.6 97% 3 7/11/2014 54 Lot 274.0 111.7 14.8 97% 3 7/11/2014 55 Lot 274.0 111.1 15.0 96% 3 7/11/2014 56 Lot 274.0 110.8 14.4 96% 3 7/14/2014 57 Lot 3/Lower Pad 273.0 107.5 12.9 93% 3 7/14/2014 58 Lot 3/Lower Pad 274.0 107.7 13.5 93% 3 7/14/2014 59 Lot 3/Lower Pad 275.0 109.0 14.9 95% 3 7/14/2014 60 Lot 3/Upper Pad FSG 105.5 15.3 92% 3 7/14/2014 61 Lot 3/Upper Pad FSG 106.1 15.6 92% 3 7/15/2014 62 Lot FSG =113.0 14.4 98% 3 7/15/2014 63 Lot 5 FSG 112.2 14.0 97% 3 7/15/2014 64 Lot FSG 111.5 13.9 97% 3 7/15/2014 65 Lot FSG 109.8 13.1 95% 3 7/15/2014 66 Lot FSG 112.0 13.6 97% 3 7/15/2014 67 Lot FSG 10.3 - 13.7 96% 3 7/16/2014 68 Lot 1 FSG 120.6 5.4 97% 2 7/16/2014 69 Lot 1 FSG 119.9 6.0 96% 2 7/16/2014 70 Lot 2 FSG 122.8 6.7 99% 2 7/16/2014 71 Lot FSG 121.0 6.9 97% 2 7/17/2014 72 Rebuild Fill Slope at Lot 3 Wall 286.0 109.2 12.5 95% 3 7/17/2014 73 Rebuild Fill Slope at Lot 3 Wall 287.0 109.5 13.8 95% 3 7/17/2014 74 Rebuild Fill Slope at Lot 3 Wall 288.0 109.9 14.0 95% 3 7/17/2014 75 Rebuild Fill Slope it Lot 3 Wall 288.0 110.6 14.2 96% 3 9/4/2014 76 Retaining Wall East of Strawberry Place 276.0 106.3 12.8 92% 3 9/4/2014 77 Retaining Wall East of Strawberry Place 275.0 103.9 13.4 90% 3 9/4/2014 78 Retaining Wall East of Strawberry Place 273.0 105.6 _12.9 92% 3 9/4/2014 79 Retaining Wall East of Strawberry Place 272.0 105.1 _13.8 91% 3 9/4/2014 80 Retaining Wall East of Strawberry Place 270.0 104.5 - _13.6 91% 3 9/4/2014 81 Retaining Wall East of Strawberry Place 269.0 11.9 - _12.1 90% 2 9/4/2014 82 Retaining Wall East of Strawberry Place 262.0 13.5 - _10.9 91% 2 9/4/2014 83 Retaining Wall East of Strawberry Place 277.5 12.9 - 11.7 91% 2 9/4/2014 84 Retaining Wall East of Strawberry Place 273.0 103.8 _13.3 90% 3 9/4/2014 85 Retaining Wall East of Strawberry Place 268.0 108.3 _13.7 94% 3 9/4/2014 86 Retaining Wall East of Strawberry Place 264.5 107.5 14.4 93% 3 9/5/2014 87 Retaining Wall South of Strawberry Place 250.0 105.7 14.1 92% 3 9/5/2014 88 Retaining Wall South of Strawberry Place 251.0 104.4 13.9 91% 3 9/5/2014 89 Retaining Wall South of Strawberry Place 252.0 106.9 14.6 93% 3 9/5/2014 90 Retaining Wall South of Strawberry Place 253.0 104.1 12.5 90% 3 9/5/2014 91 Retaining Wall South of Strawberry Place 254.0 105.4 13.8 91% 3 - 92 Not Used - - - N/A - - 93 Not Used - - - N/A - 10/10/2014 94 BackHorseshhoeSbape Wall 2'Below Top ofWall 272.0 105.1 13.2 91% 3 ** TEST FAILED, SEE RETEST TABLE I COMPACTION TEST SUMMARY Job Name: Tabata Ranch Job Address: - Lemon Leaf Drive, Carlsbad Job No. 10-1210 1G Date: 07/06/02015 Date Test No. Location Elevation or Depth Feet Density pcf Moisture Content %Dry Relative Compaction % Soil Type 10/10/2014 95 Back HorsbIioe Shape Wall 2'BeIow Top ofWall 270.0 104.8 12.9 91% 3 10/10/2014 96 267.0 104.4 13.4 91% 3 10/10/2014 97 Back Hobhoe shape Wail 2'BeIow Top ofWall 262.0 105.7 10.5 92% 3 10/10/2014 98 Back Horseshhoe Shape Wall 2'Below Top ofWall 272.0 107.9 10.9 94% 3 10/10/2014 99 BackHorshhoe Shape Wall 2'BeIow Top ofWall 270.0 107.6 11.3 93% 3 7/28/2014 100 Lower Half of Slope (Sewer) -2.0 108.2 14.9 94% 3 7/28/2014 101 Lower Half of Slope (Sewer) -1.0 106.0 15.3 92% 3 7/29/2014 102 Lower Half of Slope (N. Sewer) -1.0 106.3 14.5 92% 3 7/29/2014 103 Lower Half of Slope (N. Sewer) -2.0 105.2 15.2 91% 3 10/23/2014 104 SDI -storm drain onLonicera St 244.0 110.6 14.1 96% 3 10/23/2014 105 SD2-storm drain on Lonicera St SG 107.6 15.8 93% 3 10/27/2014 106 Storm Drain Manhole -2.0 110.2 14.6 96% 3 10/27/2014 107 Storm Drain Manhole FSG _112.3 15.1 97% 3 .10/29/2014 108 Storm Drain Tie-In SG _111.2 13.1 97% 3 10/31/2014 109 Sewer Tie-in SG 114.4 13.3 99% 3. 11/10/2014 110 8-mch Sewer Line 250.0 109.6 12.7 95% 3 .11/10/2014 _111 8-inch Sewer Line 252.0 1 112.7 12.7 98% 3 1/10/2014 _112. 8-inch Sewer Line 253.0 110.4 13.1 96% 1 3 - 1/10/2014 _113 8-inch Sewer Line 254.0 1 109.8 12.9 95% 1 3 **TEST FAILED, SEE RETEST TABLE II LABORATORY TEST DATA Job Name: Tabata Ranch Job No. 10-12101G Job Address: Lemon Leaf Drive, Carlsbad Date 7/6/2015 Maxunum Optimum Sample No. Dry Density Moisture Soil pcf Content Description. %wt. 125.9 9.5 Light brown silty SAND with rock correction 124.3 10.0 Light brown silty SAND 115.2 12.3 Yellowish brown silty SAND