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TRENCHING & BACKFILL 02 2020-10 <br />3.08 SPECIAL REQUIREMENT FOR COMPACTION IN BAY MUD <br />A. Compaction procedures are as described in paragraph "General Compaction" <br />except that the density of compaction shall be 90% as determined by ASTM <br />Designation D1557, except for the top 6" in paved areas which shall be <br />compacted to 95%. <br />B. Remove shoring or sheathing as described above, making sure that the pipe is <br />not displaced. <br />3.09 SPECIAL EARTHWORK REQUIREMENTS FOR SUBSURFACE DRAINS <br />A. Excavate to the dimensions indicated. <br />B. Provide a bedding surface of uniform density consisting of permeable material as <br />indicated in paragraph 2.02 of this specifications section. <br />C. Backfill around and over the pipes after pipe installation has been approved with <br />permeable material to the depth indicated. Place in maximum loose lifts of 8 <br />inches. <br />D. Compact each lift with mechanical tampers or rammers. Compact bedding and <br />backfill materials to 90% of ASTM D1557, Method D, maximum density. Place <br />the remainder of the trench backfill as specified. <br />3.10 SPECIAL REQUIREMENTS FOR CONTROLLED DENSITY FILL (CDF) <br />A. Applications of CDF include, but are not limited to: backfills, structural fills, <br />insulating fills, road base, slab base, trench bedding, void and abandoned tank <br />fills caisson and pile fills, abandoned pipes and culverts. <br />B. CDF shall be discharged from the mixer by any reasonable means into the area <br />to be filled, including tremie methods or elephant trunk chutes. CDF shall be <br />brought uniformly to the elevation as shown on the plans. Trench sections to be <br />filled with CDF shall be contained at either end by bulkheads of earth fill. <br />C. Permanent pavement may be placed directly upon the CDF as soon as it has <br />sufficiently self-consolidated so that the surface will withstand the process of <br />paving without displacement or disruption. If the placement of the CDF is not <br />completed early enough to allow for permanent paving to be completed the same <br />day, the contractor shall provide steel plates to span the trench and prevent <br />traffic contact with the CDF overnight or until permanent paving can be placed. <br />D. Compaction is not necessary when placing CDF. <br />3.11 FIELD QUALITY CONTROL <br />A. The Engineer will inspect, test and approve trench backfill layers before further <br />construction is permitted thereon. Number of tests required will be determined <br />by the Engineer.