Laserfiche WebLink
1 <br /> <br /> <br />LI <br /> <br /> <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br /> <br />1 <br />1 <br /> <br />1 <br /> <br />substances such as large amounts of clean sands and gravels, silts, <br />and carbonaceous or linnaceous soils and coal slag. The fill should <br />not contain any rocks or lumps over- 6 inches in diameter. <br />6. The selected fill material shall he placed in layers, which when compac- <br />ted, shall not exceed six inches. Each layer shall be spaced evenly and <br />shall be thoroughly blade mixed during the spreading to insure uniformity <br />of material in each layer. <br />7. In general, the fill material should be compacted at or somewhat above <br />the optimum moisture content specified for the soils. The contractor <br />should be required to add the necessary moisture to the backfill material <br />in the excavation if, in the opinion of the soils engineer, it is not <br />possible to obtain uniform moisture content by adding water to the fill <br />surface. <br />8. After each layer has been placed, mixed and spread evenly, it shall be <br />thoroughly compacted to not less than 95°b of maximum density in accord- <br />ance with ASTh1 D-1557-70. Compaction shall be by sheepsfoot rollers, <br />segmented steel wheeled rollers or pnewnatic tired rollers. Compaction <br />should be accomplished while tare raterial is at the specified moisture <br />content. Compaction of eactr layer sirail be continuous over its entire <br />area. However, fill placement helow the water table may have to be per- <br />formed in sections so that the dewatering operations Can be carried out. <br />The compaction equipment shall make sufficient trips to Insure that the <br />required density has been obtained. It is important that fill be compac- <br />ted tight against abutments. A trand operated compactor may be needed. <br />9. Field density tests should be made by the soils engineer of each layer <br />of fill. Sufficient tests will be made to determine the adequacy of <br />the fi71. The frequency of testing will be determined by the Soils <br />-7- <br />1 <br />