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TRENCHING & BACKFILL 02 2020-7 <br />F. The Engineer shall have the right to limit the amount of trench which is opened or <br />partially opened at any one time; and also to limit the amount of trench left <br />without backfill, at any one time. <br />G. No trench or holes shall be left open overnight. Use steel plates to protect open <br />trenches overnight. <br />H. Excavation for thrust blocks shall be neat to the line and dimensions shown or <br />called for on the plans. <br />I. Provide for dewatering trenches and excavations and subsequent control of <br />ground water, utilizing such pumps or other equipment as may be necessary to <br />control ground water and seepage until backfilling is completed. <br />3.02 GENERAL BEDDING <br />A. Utilities shall be laid on a firm layer of firm bedding material not less than four (4) <br />inches in depth as shown or as noted on the plans and detail drawings, except <br />that bedding shall not be required for utilities two (2) inches or less in nominal <br />diameter. Compact as specified herein. <br />B. Upon completion of bedding operations and, prior to the installation of pipe or <br />appurtenances, notify the Engineer who will then inspect the bedding layer. Pipe <br />laying shall not commence until the bedding has been approved. <br />3.03 GENERAL BACKFILLING <br />A. Backfill shall be as shown on the plans. Place in 6-inch maximum loose lifts to <br />one foot above pipe unless otherwise specified. Bring up evenly on each side, <br />and for the full length of the structure. Ensure that no damage is done to <br />structures or protective coatings thereon. Place the remainder of the backfill in 8- <br />inch maximum loose lifts unless otherwise specified. Compact each loose lift as <br />specified in Paragraph 3.04 "General Compaction" before placing the next lift. <br />Where unacceptable settlements occur in trenches and pits due to improper <br />compaction, excavate to the depth necessary to rectify the problem, then backfill <br />and compact the excavation as specified herein and restore the surface to the <br />required elevation. <br />B. No backfill shall be placed until the line has been inspected and approved for <br />backfilling. <br />3.04 GENERAL COMPACTION <br />A. Use hand-operated plate type vibratory or other suitable hand tampers in areas <br />not accessible to larger rollers or compactors. Be careful to avoid damaging <br />pipes and protective pipe coatings. Compaction shall be in accordance with the <br />following unless otherwise specified. If necessary, the Contractor's selected <br />equipment and construction procedure shall be altered, changed or modified in <br />order to meet the specified compaction requirements.