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processing cannot adequately improve the condition, should be overexcavated down to <br />firm ground and approved by the soil engineer before compaction and filling operations <br />continue. Overexcavated and processed soils, which have been properly mixed and <br />moisture conditioned, should be re-compacted to the minimum relative compaction as <br />specified in these guidelines. <br />Existing ground, which is determined to be satisfactory for support of the fills, should be <br />scarified to a minimum depth of 6 to 8 inches, or as directed by the soil engineer. After the <br />scarified ground is brought to optimum moisture content, or greater and mixed, the <br />materials should be compaded as specified herein. If the scarified zone is greater than <br />6 to 8 inches in depth, it may be necessary to remove the excess and place the material <br />in lifts restricted to about 6 to 8 inches in compacted thickness. <br />Existing ground which is not satisfactory to support compacted fill should be overexcavated <br />as required in the geotechnical report, or by the on-site soils engineer and/or engineering <br />geologist. Scarification, disc harrowing, or other acceptable forms of mixing should <br />continue until the soils are broken down and free of large lumps or clods, until the working <br />surface is reasonably uniform and free from ruts, hollows, hummocks, or other uneven <br />features, which would inhibit compaction as described previously. <br />Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical <br />[h:v]), the ground should be stepped or benched. The lowest bench, which will act as a <br />key, should be a minimum of 15 feet wide and should be at least 2 feet deep into firm <br />material, and approved by the soil engineer and/or engineering geologist. In fill over cut <br />slope conditions, the recommended minimum width of the lowest bench or key is also <br />15 feet, with the key founded on firm material, as designated by the geotechnical <br />consultant. As a general rule, unless specifically recommended otherwise by the soil <br />engineer, the minimum width of fill keys should be approximately equal to 1,6 the height of <br />the slope. <br />Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable <br />material. Benching may be used to remove unsuitable materials, although it is understood <br />that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered <br />for unsuitable materials in excess of 4 feet in thickness. <br />All areas to receive fill, including processed areas, removal areas, and the toes of fill <br />benches, should be observed and approved by the soil engineer and/or engineering <br />geologist prior to placement of fill. Fills may then be properly placed and compacted until <br />design grades (elevations) are attained. <br />Pacific Development Group <br />Filelserverandree4900497681.foundshopctr <br />Appendix F <br />Page 3