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Project No. JB-569 20 June 2006 Revised 18 October 2006 Page 9 Table 2 IMPORTED MATERIAL REQUIREMENTS Sieve Size Percent Passing 6 inches (150 mm) 100 4 inches (100 mm) 95 - 100 #200 5-25 Plasticity (PI) = 12 or less Liquid Limit ILL) = 30 or less Clay soils should not be allowed to dry out and crack. Any dried clay soils should be wetted until they reach acceptable moisture contents or they can be excavated and replaced with acceptable properly compacted fill. 6.1.5 Cut Slopes Cut slopes should not be steeper than 2H:1 V. We recommend all cut slopes be evaluated by our engineering geologist during earthwork operations. If adverse bedding or other zones of weakness either in the bedrock or soil materials are encountered additional recommendations will be provided. Grading should be in accordance with the Vineyard Avenue Corridor Specific Plan. 6.1.6 Fill Slopes Fill slopes should not be steeper than 2H:1 V. For fill placed on native or cut slopes or reconstructing a slope area, we recommend that a keyway be excavated at least 3 feet into the underlying competent bearing soil or bedrock at the toe of the proposed fill as shown on Figure 9, Typical Buttress and subdrain. The bottom of the keyway must be a minimum width of 10 feet and be sloped a minimum of 2 percent downward into the hillside. The total depth and width of the keyway and the extent of the fill slope configuration will be determined in the field during grading by our representative. A subdrain system must be installed in the keyway to collect migrating water. The subdrain system should consist of %z by '/a-inch clean drain rock wrapped in an approved filter geotextile with a perforated rigid 4-inch-diameter PVC (sch. 80) or equivalent pipe installed on a bed of approximately 3 inches of drain rock. Class 2 Permeable drain rock is and acceptable equivalent for drain rock and geotextile. The subdrain must be placed at the heel (rear) of the keyway/bench with perforations placed downward. The subdrain should be extended to an acceptable outlet using unperforated pipe outside of the drain rock. All subdrain and outlet drain pipe must be placed to fall at least 1 percent. K.~rbrnacFier Engineering, Inc.