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curve. During construction, placement of select fill shall conform to the <br />following requirements: <br />a. The minimum allowable dry density shall be no less than 90 percent <br />o£ maximum dry density. <br />b. The allowable moisture content range shall be +/- 3 percent of <br />optimum. <br />3.1.2 Topsoil <br />Testing shall be performed on representative samples of each principal type <br />or combination of topsoil materials. At least one set of tests shall be <br />performed on each borrow source proposed. Testing shall consist of the <br />determination of maximum particle size in accordance with ASTM D 922, pH in <br />accordance with ASTM D 4972, and organic content in accordance with ASTM D <br />2979. <br />3.1.3 Chemical Contaminatio^ Testing <br />Borrow used for the select fill and topsoil layers shall be free of <br />contamination. Each proposed borrow source shall be sampled and analyzed <br />for chemical contamination in accordance with Section 01450 CHEMICAL DATA <br />QUALITY CONTROL. <br />3.1.4 Filter Criteria <br />Soil lifts of different soil types, that are not separated by geosynthetic <br />material, shall conform to gradation requirements for natural filters. <br />Guidance is provided in EM 1110-2-1901, 1993, Appendix D - Filter Design. <br />An example specification is provided in Attachment A - Table 2. Attachment <br />A Figure 1 provides the result of the calculation. <br />3.2 INSTALLATION <br />3.2.1 Select Fill <br />3.2.1.1 Initial Lift of Select Fill Placed Over Geosynthetics <br />Low ground pressure equipment with ground pressures less than 7 psi shall <br />be used to place and traffic compact the first lift of select fill. <br />Traffic compaction shall consist of a minimum of 2 passes over all areas. <br />3.2.1.2 Subsequent Lift of Select Fill <br />The loose lift thickness of each subsequent lift shall be no greater than 8 <br />inches. Low ground pressure equipment shall be used to place the second <br />lift of select fill. Full scale placement and compaction equipment shall <br />be allowed on areas underlain by geosynthetics only after the second loose <br />lift of soil has been placed. Hand operated compaction (one way plate <br />compactor) shall be used within three feet of the slope face of the soil <br />lifts. No compaction equipment shall be allowed within 1.5 ft of the slope <br />02340-8 <br />