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3.10 TREATMENT FOR TOP OF TRENCH <br /> Upon completion of backfill placement,and before drying of the mixed backfill can occur,the trench shall be <br /> capped with clayey soils with a nominal thickness of one foot as measured at the centerline of the trench with <br /> side slopes of 3:1 as measured from the existing ground surface. Clayey soils for capping the cutoff trench will <br /> be borrowed from the existing on-site overburden areas. <br /> 3.11 CLEAN-UP <br /> After completion of the backfill and capping,the surrounding areas shall be graded to match the existing <br /> ground and all remaining excavated material and slurry shall be spread out over the backfill mixing area with <br /> at least 10'separation from the slurry wall. The Owner shall be responsible for all other reclamation activities, <br /> including final regrading of the site(including temporary construction easements),and repairing existing <br /> structures such as ditches and fences. All construction debris shall be removed from the site prior to <br /> demobilization. <br /> 3.12 QUALITY CONTROL <br /> The Engineer shall maintain the quality control for the slurry wall construction. Quality control shall be <br /> performed in accordance with these Specifications. Laboratory permeability testing of the backfill shall be <br /> performed by a third party as approved by the Engineer and Owner. Minimum testing requirements to which <br /> the Contractor will be required to comply with are summarized on Table 1 as specified herein. <br /> 3.13 TRENCHING CONTINUITY AND KEY <br /> The Contractor shall demonstrate that the trench is continuous and keyed to a depth not less than the minimum <br /> specified depth into the underlying aquiclude. Trench continuity shall be verified by the action of movement <br /> of the trench excavation equipment such that the digging tools can be passed vertically from top to bottom of <br /> the trench,as well as moved horizontally along the axis of the trench without encountering unexcavated <br /> material. Penetration of the bottom of the trench into the suitable bedrock shall be demonstrated by <br /> observation of the cuttings removed from the trench and by direct measurement of trench depth by the Slurry <br /> Trench Specialist or Quality Control Representative. <br /> 3.14 SLURRY AND BACKFILL <br /> Testing requirements for slurry and backfill are as follows: <br /> A. Bentonite <br /> Certification of compliance with the specifications for each shipment shall be obtained from the <br /> material manufacturer. <br /> B. Slurry Introduced in the Trench <br /> A complete series of tests shall be conducted on slurry introduced in the trench at least twice per shift <br /> when slurry is mixed and pumped to the trench. Filtrate loss test frequency can be reduced to one per <br /> week once 3 consecutive passing tests are achieved with no failing tests. These tests shall include <br /> (see Table 1): <br /> Unit weight of the slurry by Mud Balance(API Standard 1313-1) <br /> - Filtration loss of the slurry(refer to API Standard 1313-1) <br /> - Viscosity of the slurry(refer to API Standard 1313-1) <br /> - pH of the slurry(refer to API Standard 1313-1) <br /> C. Slurry in the Trench <br /> February 2016 Section 02168-Page 5 of 6 <br />