Laserfiche WebLink
<br /> <br /> <br /> <br /> <br /> <br />fill. The test pad indicated that no appreciable wmpaction of the noncohesive materials were <br />obtained after two passes of the vibratory roller was made on a standard lift of the material dumped <br />by the 631 Cat scrapers. This data was used to establish the method specification for the <br />compaction of the embanlonent materials. <br />The main embanlanent construction was completed in mid October 1990 with the exception of the <br />slope shaping and grading and construction of the access road, which was completed in late <br />November 1990. Approximately 995,000 CY of material was placed in the main embankment fill. <br />SRK as-built Drawings 14711-102 and 104 depict the fmal embanlvnent shape and the zoning of the <br />structure. <br />' 3.2 Sputter Embsnl®ent <br />The sputter embanlanent was constructed using random fill (Type 4) material with the exception <br />' of the Type 1 material that was placed over the synthetic liner. SRK as-built Drawing No. 14711- <br />113 depicts the final grading and sections of the sputter embanlQnent construction. Construction <br />' of the sputter embankment fill wmmenced on November 1, 1990 and was completed in mid- <br />November 1990. <br />1 <br /> <br />1 <br /> <br /> <br /> <br /> <br /> <br /> <br />A 60-ft wide channel was excavated through the foundation of the sputter embanlmtent to allow <br />positive drainage along the synthetic liner surface and underdrain piping system from the upper <br />impoundment to the lower impoundment. The channel excavation was in excess of 30-ft below <br />natural ground level in the deepest location. The final elevation of the channel floor was raised <br />approximately 13-ft because saturated clayey sands were encountered during the excavation. The <br />materials began displacing under the load of the rubber tired heavy equipment. fnsitu density tests <br />were performed on the materials which indicated that the material was very dense and well <br />consolidated due to the overburden which had confined the material prior to the excavation. Test <br />pits indicated that ground water was traveling horiwntally through the area in lensres of sands and <br />gravels and was ttnable to percolated down wards due to horizontal strata of clayey sands. Based <br />on the data generated from the test pits and the insitu densities, it was determined that the material <br />was a natural drainage channel for the shallow subsurface waters in the valley and the natural <br />channel should not be disturbed during construction. The top 4-ft of the channel invert was over <br />excavated, and 3-ft of well graded sandy gravel was placed through the channel to allow the shallow <br />ground water to migrate as required. A 4-in diameter corrugated/perforated FIDGPE pipe with a <br />filter sock was also placed in the subsurface underdrain layer to enhance the flow capacity of the <br />drainage layer. The subsurface underdrain was capped with the standard one fmot of silt liner <br />bedding. A detail of the subsurface underdrain is depicted on SRK as-built Drawing No. 14711-106. <br />11 <br /> <br />