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Home My WebLink AboutGeotechReportPreciseGrading(Sept.15,1998) � .. • • �� • � Geotechnical � Geologic • Environmental 24890 Jefferson Ave. � Murrieta, California 92564 •(909) 677-9651 • FAX (909) 677-9301 September 15, 1998 W. O. 2461-B-SC US Home Central California Division 4371 Latham Street, Suite 204 Riverside, California 92501 Attention: Ms. Tina Mokhtarzadeh, Land Development Manager Subject: Geotechnical Report of Precise Grading, Lots 1 through 11, Tract 24232 and Lots 8 9, Tr�ct 2�220, City of Temecula, Riverside County, California. In accordance with your request, this final geotechnical report of precise grading is provided for Lots 1 through 11 of Tract 24232 and Lots 28 and 29 of Tract 23220, City of Temecula, Riverside County, California. This sites were previously graded under the observation and testing services of South Coast Geologic Services, Inc. (Appendix). Precise grading within the subject project, under purview of this report, began in August of 1998, and was completed in September of 1998. PREPARATION OF EXISTING GROUND 1. Major vegetation was removed prior to grading. 2. The lots were scarified to a depth of about 12 inches, brought to at least optimum moisture content, then compacted to a minimum relative compaction of 90 percent of the laboratory standard ASTM D-1557. 3. Major ruts and rills that existed in the lots or associated slopes were cleared of loose soils, scarified, moisture conditioned and compacted to 90 percent of the laboratory standard, as necessary. 4. Existing retaining walls on Lots 3, 4, and 11 in Tract 24232 were removed. Remedial removal of the soils located beneath the wall footings were removed to at least 1 foot below the footing of proposed new walls. � • • FILL PLACEMENT The scarified fills and fill associated with the retaining wall footing areas were compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. Only compacted fills placed during this phase of grading are reported herein. For information regarding compacted fill materials placed on the site during the previous phase of grading refer to the referenced reports (Appendix). FIELD TESTING 1. Field density tests were performed using the nuclear-densometer method ASTM D-2922. 2. Field density tests were taken at periodic intervals and selected locations to check the compactive effort provided by the contractor. If test results indicated less than the required minimum compaction and/or required minimum moisture content, the contractor was notified and the area was reworked until the required minimum relative compaction was achieved for each respective area. 3. Visual classification of the soil in the field was the basis for determining the maximum density value to use for a given density test. 4. Compaction tests have been numbered in a continuous sequence for all of the tract. Only the tests taken on the subject lots are included in this report. LABORATORY TESTING Maximum Density Testina The laboratory maximum dry density and optimum moisture content for the major soil type was determined according to test method ASTM D-1557. The following table presents the results. Soil T e Maximum Dr Densit c O timurn Moisture:Gontent A - Silty Sand, Brown, Fine Grained 122.0 12.5 US Home W.O. 2461-B-SC Tracts 24232 and 23220, City of Temecula September 15, 1998 e:\wp7\murr\sc2400\2461 b.crg Page 2 GeoSoils, Inc. ' • • Expansion Potential Expansion Index tests were performed for the typical foundation soil types exposed at pad grade in general accordance with Standard #18-2 of the Uniform Building Code (1994). Based on the test results obtained which varied from 0 to 11, the expansive potential of the soils for the subject lots is classified as Very Low to Low (i.e., Expansion Potentials between 0 - 50). Soluble Sulfates Representative samples of the site materials were collected for soluble sulfate testing. Based on the test results obtained, which varied from 18 to 23, and the latest edition of the Uniform Building Code (UBC), the soluble sulfate content is categorized as negligible (0- 150 ppm) and sulfate-resistant concrete will not be necessary. CONCLUSIONS AND RECOMMENDATIONS Recommendations for foundation design parameters, foundation construction, and utility trench backfill were presented in GSI (1998a and 1998b), dated June 8, 1998 and July 29, 1998, respectively. All findings, conclusions and recommendations in those reports remain pertinent and applicable except as superseded herein. REGULATORY COMPLIANCE Processing of original/existing ground and placement of compacted fills under the purview of this report have been completed under the observation of and with selective testing provided by representatives of GeoSoils, Inc. and are found to be in general compliance with the Grading Code of the City of Temecula and the County of Riverside. Our findings were made in conformance with generally accepted professional engineering practices and no further warranty is implied or made. GeoSoils, Inc. assumes no responsibility or liability for work, testing, or recommendations performed or provided by others. This report is subject to review by the controlling authorities for this project. US Home W.O. 2461-B-SC Tracts 24232 and 23220, City of Temecula September 15, 1998 e:\wp7\murr\sc2400\2461 b.crg Page 3 GeoSoils, Inc. . � • The opportunity to be of service is sincerely appreciated. If you shouid have any questions, please do not hesitate to contact our office. � Respectfully submitted ��Q�OFESSPp�,� ��En �F y ,��, ��PS R. ,�� Fy GeoSoils, Inc. ` 5'� Q F , q � �,� � �� 's� �� , � .r� �'g- � No. 476 � a, � 0 �� N Exp. -30-01 ' ° � � No. 1340 —i � � � Ce�;,'s`scd J' �TFCHN��'� John P. Franklin s G ologst� Albert R. Kleist �'��'oFC��F��'�� Engineering Geolo � Geotechnical Engineer, �F CAL�F J P F/AR K/rs Enclosures: Table 1- Field Density Test Summary Appendix - References Distribution: (6) Addressee US Home W.O. 2461-B-SC Tracts 24232 and 23220, City of Temecula September 15, 1998 e:\wp7\murr\sc2400\2461 b.crg Page 4 GeoSoils, Inc. ' • • W.O. 2461-B-SC TABLE 1- FIELD DENSITY TEST SUMMARY Page 1 �"`��U�S�Homes�"e ��Tracts�23220narid 24232��, ��ELE O� 6MOISTa= QRY D NE ,-..r%a'��.� .;��F�S,DIL�;I �� .�.�._,��.�.� ��....._.�.� � l' �ST��*� fy ��pATE ,a ,� . �� L ITTQ RACT�NU(t116ER�, �u� ��',�'� E�.1 PTH� `GONT %a:. C .. _„ . �,; �xCQMP �tMETF��TYP i 1 8-31-98 Lot 28/23220 � FG 13.6 114.9 94.2 N A 2 8-31-98 Lo 29/23220 FG 13.4 118.8 97.4 N A -- --.. 3 8-31-98 Lot 8/24232 ' FG 12.9 ' 116.2 95.2 __ N__ A __ 4 i 8 -31-98 Lot 9/24232 FG 14.1 111.8 9 1.6 N A 5 8-31-98 L ot 10/2 FG 14.3 115.3 94.5 N A 6 8- 31-98 Lot 7/24232 FG 13.9 113.6 93.1 N A ---- ------------------------- - -------.:- -- -- 7�_ 8-31-98 _ Lot 6/24232 _______ F __ 14.7 114.1 93 _ N A 8 � 8-31-98 Lot 5/24232 FG 13.5 115.8 94.9 N A 9 9-3-98 Lot 4/24232 - Ret. Wall 1269.0 9.5 105.1 ' 86.1 N A 9 A� 9-3-98 Lot 4/24232 - Ret. Wall 1269.0 ' 12.7 110.9 � 90.9 N A 10 i � 9-3-98 Lot 4/24232 - Ret. Wall 1271.5 13.0 111.3 91.2 N A 11 9- 3-98 Lot 3/24232 - Ret. Wall ; 1266.5 15.2 111.1 91.1 N A 12 9-3-98 Lot 3/24232 - Ret. Wall 1268.0 14.1 113.2 92.8 _ N A___ 13 ', 9-3-98 Lot 1/24232 FG 12.7 116.6 95.6 _ N _ A _ 14 ; 9-3-98 Lot 2/24232 FG _ 12.6 114.2 93.6 N _ A 15 9-3-9 Lot 11 /24232 FG 13.1 112.3 92 .0 N A - -- - --- --- - ---- ---- -- 16 9-3-98 Lo t 4/2 FG 12.8 112.9 92.5 N A - ---------------- -- - ----------------------- - 17 9 -3-98 Lot 3/24232 FG 12.7 114.7 94.0 __ N_ A_ 18 9-4-98 Lot 11/24232 - Ret. Wall 1271.0 12.9 111.3 91.2 N A 19 9-4-98 Lot 11 /24232 - Ret. Wall 1273.0 13.1 115.5 94.7 __ N A__ 20 ' 9-4-98 Lot 11 /24232 - Ret. Wall 1249.0 13.4 113.8 9 3.3 N A 21 9-4-98 Lot 11 /24232 - Ret. Wall 1259.0 12.8 17 2.2 92.0 N __ A__ LEGEND N NUCLEAR DENSOMETER FG FINISH GRADE A INDICATES RETEST GeoSoils, Inc. ' � • APPEIVDIX References GeoSoils, Inc., 1998a, Soil Parameters for the Proposed Loffelstein or Crib Type Wall, Tract 24232-Lots 1 through 11, Temecula, California, W.O. 2461-A.1-SC, dated July 29. , 1998b, Geotechnical investigation of Hydroconsolidation and Associated Differential Settlement Potential, Existing Graded Parcels, Tract 24232-Lots 1 through 11 and Tract 23220-Lots 28 and 29, Temecula, Riverside County, California, W.O. 2461-A-SC, dated June 8: South Coast Geologic Services, Inc., 1991, Rough Grade Compaction Report for Lots 1 through 11, Tract 24232, Riverside County, dated January 11. , 1989a, Rough Grade Compaction Report for Lots 1 through 29, Tract 23220, Riverside County, California, dated October 10. , 1989b, Geotechnical Report for a Proposed Subdivision Consisting of 11 Single Family Homes within the 4.91 Acre Parcel Described as Tentative Tract 24232, Located Southeasterly of the Intersection of Nicolas Road and Calle Medus, Riverside County, California, dated April 24. GeoSoils, Inc.