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Grading Guide Specifications Page 4 <br />Foundations <br />• The foundation influence zone is defined as extending one foot horizontally from the out:side <br />edge of a footing, and proceeding downward at a 1/2 horizontal to 1 vertical (0.5:1) <br />inclination. <br />• Where overexcavation beneath a footing subgrade is necessary, it should be conduded so <br />as to encompass the entire foundation influence zone, as described above. <br />• Compacted fill adjacent to exterior footings should extend at least 12 inches above <br />foundation bearing grade. Compacted fill within the interior of structures should extend to <br />the floor subgrade elevation. <br />Fill Sloges <br />• The placement and compadion of fill described above applies to all fill slopes. Slope <br />compaction should be accomplished by overfilling the slope, adequately compading the fill <br />in even layers, including the overfilled zone and cutting the slope back to expose the <br />compacted core <br />• Slope compadion may also be achieved by backrolling the slope adequately every 2 to 4 <br />vertical feet during the filling process as well as requiring the earth moving and compaction <br />equipment to work close to the top of the slope. Upon completion of slope construdion, the <br />slope face should be compacted with a sheepsfoot connected to a sideboom and then grid <br />rolled. This method of slope compadion should only be used if approved by the <br />Geotechnical Engineer. <br />• Sandy soils lacking in adequate cohesion may be unstable for a finished slope condition and <br />therefore should not be placed within 15 horizontal feet of the slope face. <br />• All fill slopes should be keyed into bedrock or other suitable material. Fill keys should be at <br />least 15 feet wide and inclined at 2 percent into the slope. For slopes higher than 30 feet, <br />the fill key width should be equal to one-half the height of the slope (see Plate D-5). <br />• All fill keys should be cleared of loose slough material prior to geotechnical inspedion and <br />should be approved by the Geotechnical Engineer and governmental agencies prior to filling. <br />• The cut portion of fill over cut slopes should be made first and inspected by the <br />Geotechnical Engineer for possible stabilization requirements. The fill portion should be <br />adequately keyed through all surficial soils and into bedrock or suitable material. Soils <br />should be removed from the transition zone between the cut and fill portions (see Plate D- <br />2). <br />Cut Slopes <br />• All cut slopes should be inspeded by the Geotechnical Engineer to determine the need for <br />stabilization. The Earthwork Contractor should notify the Geotechnical Engineer when slope <br />cutting is in progress at intervals of 10 vertical feet. Failure to notify may result in a delay <br />in recommendations. <br />• Cut slopes exposing loose, cohesionless sands should be reported to the Geotechnical <br />Engineer for possible stabilization recommendations. <br />• All stabilization excavations should be cleared of loose slough material prior to geotechnical <br />inspection. Stakes should be provided by the Civil Engineer to verify the location and <br />dimensions of the key. A typical stabilization fill detail is shown on Plate D-5.