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than-specified Drain Cover Fill material, the liner showed no distress in any areas where the <br />cover was 18" or more. Further, the equipment involved was a D-8N which was not equipped <br />with low-ground-pressure tracks. For Phase II construction with atwo-foot thickness, Drain <br />Cover Fill will be placed with low ground pressure-equipped D-8 or D-7 equipment, or smaller <br />standard or low ground pressure equipment. This, we believe the OMLR will agree, will further <br />reduce the potentials for compromise of the liner. <br />Remedial measures for areas of Drain Cover Fill with less than 2.0 feet thickness over synthetic <br />liner (where equipment is likely to traverse the area) are described next. As stated previously, <br />should the Drain Cover Fil] be determined to have been placed at a thickness less than 2.0 feet, <br />additional material shall be placed to meet the 2.0 foot minimum prior to running the Drain <br />Cover Fill equipment (e.g., a low ground pressure dozer) across that area again (other than to <br />place the requisite Drain Cover Fill). However, should the Drain Cover Fill be determined to <br />have been placed at less than 1.5 feet in thickness (as determined by the satellite surveying <br />system) and the material has been traversed by dozers placing that Drain Cover Fill, the Drain <br />Cover Fill in the entire area that is both too thin (< 1.5 feet) and has been traversed by a dozer <br />will be carefully removed from the liner by the contractor under direct supervision of the CQA <br />inspector, to expose the liner. If the liner appears to have imperfections, the suspect areas will <br />be tested, repaired as necessary, and retested after repairs. Upon passing applicable tests, the <br />repaired area will be properly re-covered with Drain Cover Fill. All such remedial measures <br />will be documented by the CQA inspection staff. <br />Further, if there is evidence that Drain Cover Fill placing equipment traversing less than 2.5 feet <br />of Drain Cover Fill has turned a circle with a radius of less than 20 feet on the Drain Cover Fill <br />that has been placed on the synthetic liner at a depth of less than 2.5 feet, or that the tracks of <br />the equipment have dug into the Drain Cover Fill (as a result of an inappropriate push of too <br />much material, sudden starting, or sudden stopping of the dozer), placed at a depth of less than <br />2.0 feet thickness in a manner that has left a track imbedded into the surface of the Drain Cover <br />Fill of greater than 6.0 inches (which indentation would be expected, the area potentially <br />affected, as determined by the CQA inspector, Drain Cover Fill will be removed to expose the <br />liner in this immediate area and if the liner appears to have imperfections, the suspect areas will <br />be tested, repaired as necessary, and retested. <br />The OMLR computed the instantaneous vertical loading of the synthetic liner by equipment using <br />foundation criteria of Lambe and Whitman. For the Drain Cover Fill loading scenarios, Golder <br />Associates computed the average pressure rather than the maximum. Use of the average is <br />standard industrial practice. It can be agreed between CC&V and the OMLR that there are <br />many methods that can be used to approximate the pressures and forces exerted on the synthetic <br />liner as a function of depth of the Drain Cover Fill and equipment. Therefore, the OMLR <br />agrees that each method must make simplifying assumptions regarding such variables as the <br />shape of the stress distribution, soil properties, and characteristics of dynamic loading. As the <br />OMLR recalls, the synthetic liner has been tested to a pressure of 385 psi for a period of 24 <br />hours. This provides a significant factor of safety between the computed instantaneous load and <br />the resistance to puncture of the synthetic material. <br />8 <br />