4620 SEAHURST AVE 2020-05-20 - Laserfiche WebLink

March 7, 2011 Mr. Paul ThompsonlKolbear, Inc. L&A Job No. 11-001 • Page 8 SITE PREPARATION AND GENERAL GRADING Vegetation within construction limits. should be cleared and grubbed. Fill, topsoil, unsuitable soil in the root zone and loose weathered soils should be completely stripped within building pads of the residences and in areas subject to traffic and structural load. The exposed soils should be compacted to a non-yielding state, as required, with a vibratory compactor and proof- rolled with a piece of heavy earthwork equipment. EXCAVATION AND FILL SLOPES Under no circumstance should excavation slopes be steeper than the limits specified by local, state and federal safety regulations if workers have to perform construction work in excavated areas. Unsupported temporary cuts greater than 4 feet in height should be no steeper than 1H:1V in fill, topsoil and weathered soils of silty fine sand, and may be vertical in the underlying very- dense, fresh till and dense advance outwash soils provided that the overall depth of excavation does not exceed 12 feet. Otherwise, cuts in fresh till and advance outwash soils should be no steeper that 3/4H:1V. Permanent cut banks should be no steeper than 2-1/4H:1V in the fill and topsoil, no steeper than 2H:1V in weathered soil, and no steeper than 1-1/2H:1V in fresh till and advance outwash soils. The soil units and the stability of cut slopes should be observed and verified by a geotechnical engineer during excavation. Permanent fill embankments required to support structural load should be constructed with compacted structural fill placed over proof-rolled, undisturbed, fresh, very-dense till and/or dense advance outwash soil after the unsuitable surficial soils are stripped. Fill embankments placed over areas steeper than 15% grade should be structurally supported. Sloping ground steeper than 15% grade should be benched with vertical steps not exceeding 4 feet tall after stripping of the surficial unsuitable soils and prior to constructing permanent fill embankment. The slope of LIU & ASSOCIATES, INC.