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Project No. 9929.G Geotechnical Investigation/Vineyard Avenue, Pleasanton 8 August 2003 <br />11. If any loose or soft soil is encountered, it must be excavated to firm/stiff native ground. <br />The upper soil zone within the portions of the swale areas to receive fill may need to be removed <br />prior to fill placement and is dependent on the time of year the grading occurs. In addition, all <br />soft and wet material from the stock pond is to be excavated until non-yielding soil is <br />encountered. If the grading occurs in or soon after the winter rain season, there is a tendency that <br />these areas will contain wet, soft deposits not suitable for the placement of fill without mitigation <br />measures. The removal of soil in Swale areas, if necessary, will be evaluated at the time of <br />grading. For contingency purposes, it should be anticipated that up to 2 feet of Swale cleaning <br />may be required. Materials generated from loose/soft soils may be used as engineered fill with <br />the approval of the Soil Engineer provided they do not contain debris. It is noted that significant <br />processing and aerating may be required if these materials are used when they are wet. <br />12. If encountered, all vegetable matter, trees, root systems, shrubs, debris, and organic topsoil <br />shall be removed from all structural areas and areas to receive fill. Trees must be property grubbed <br />and the major root systems removed. <br />13. It will be necessary to install subsurface drains beneath the fills to be placed in the Swale <br />areas. This is necessary in order to provide drainage to these areas and to ensure stability of the <br />fills and provide a stable base for placement of fill, where required. Atypical detail of a Swale <br />subdrain has been included as Figure 7 in Appendix A. The location and extent of any subdrains <br />will be determined in the field by the Soil Engineer during the grading operations after cleaning <br />of the swale is performed. <br />14. Following stripping and removal of any loose and/or soft soil, the top 8 inches of exposed <br />native ground for fill areas should be scarified and compacted to a minimum degree of relative <br />compaction of 90% at a moisture content 2 to 3% above optimum as determined by ASTM <br />D1557-91 Laboratory Test Procedure. <br />TERRASEARCH, inG Page 14 of 53 <br />