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Foothill Sanitary Landfill — Module 1 December 2003 <br />County of San Joaquin Job No 031602 00 02 <br />be reworked. Once the surface preparation was complete, the area was approved for <br />geosynthetics placement. A subgrade acceptance form was prepared by Vector's CQA <br />Monitor and signed by D&E prior to any geosynthetics placement. Subgrade <br />acceptance forms are presented in Appendix D. <br />4.3 Sideslope Subgrade Preparation <br />The 3:1 sideslopes of Module 1 were prepared by moisture conditioning and <br />recompacting the existing top 6 -inches of soil to meet WDR Construction Specifications <br />2(c). The material was compacted in place with a CAT 815 sheepsfoot compactor. <br />Moisture was added with a water truck and mixed into the soil during compaction. <br />Vector's CQA Monitor obtained samples of the material and performed sieve analyses <br />(including a sieve wash). Location of the samples collected are shown in Figure 2. <br />Unlike the foundation layer, the sideslope subgrade did not have a specified <br />requirements for percent fines. After the sideslopes were recompacted, field density <br />dbtests were conducted with a nuclear density gauge to ensure 90% relative compaction. <br />The moisture content of the sideslope subgrade was determined by the oven drying <br />method (ASTM D2216) to ensure an in-place moisture content of 0 to 4% wet of <br />optimum. The dry density obtained by the nuclear gauge was modified based on the <br />oven dry moisture content. This modified value for the dry density was utilized in <br />determining pass or fail for compaction. Test locations are shown in Figure 5. <br />• Grain Size Analysis of Subgrade Soils <br />The CQA testing for the sideslope subgrade soils consisted of sieve analysis (ASTM <br />D-422) and sieve wash (ASTM D-1140), once per 10,000 cy. In addition, visual soil <br />descriptions and soil classifications were performed on the samples collected for <br />sieve analyses. Three (3) sieve analysis tests were performed. The percent minus <br />the No. 200 sieve for the foundation layer material ranged from 30.7% and 56.7%. <br />Detailed results of the subgrade material testing is included in Appendix E. <br />Vector Engineering, Inc. • 143E Spring Hill Drive • Grass Valley, CA 95945 • (530) 272-2448 <br />15 <br />