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BACKFILL EXISTING <br />TRENCH WITH NATIVE <br />MATERIALS <br />' TYP. SANDY CLAY <br />1.5 OVERBURDEN <br />., <br />3,-5' <br />VARIES ASTM . G33-7, . <br />CONCRETE. <br />AGGREGATE `. <br />2' <br />(MIN) . . . . . . <br />ASTM C33 <br />: CONCRETE SAND <br />(IF REQUIRED) VANES .. : _ 4.0' <br />, : <br />�. <br />SAND AND GRAVEL <br />4 ALLUVIUM <br />.05 <br />. 0!5' TYP. <br />1.5 _ q(TYP.) ( �. <br />3' <br />4' <br />PERIMETER DRAIN DETAIL (TYPICAL SECTION IF REQUIRED) <br />VARIES <br />LL- <br />�. o <br />Z <br />o z <br />z <br />'moo 25' <br />m <br />�_ <br />0-: � X J <br />Ow I <br />XW J Q <br />cL CL (n <br />NATIVE ` <br />MATERIAL <br />OVERBURDEN AND TOPSOIL <br />BACKFILL ALL DISTURBED AREAS <br />DOWN TO WATER SURFACE <br />MEN Mt., azwoloac2p IIIIIIIIIIINMI11 <br />TYPICAL BACKFILL SECTION. <br />N.T.S. <br />SLURRY WALL NOTES: <br />1. Bentonite Specifications <br />YP/PV ratio API Std. 13A less than 3 <br />Viscometer greater than 30 <br />Filtrate Loss less than 15 cm3 <br />Moisture Content ASTM D 2216 less than 10 percent <br />Test results for each lot of bentonite must be provided. <br />2. Water Specifications <br />pH 6-8 <br />Hardness less than 200 ppm <br />Total Dissolved Solids less than 500ppm <br />Oil, organics, acids, alkali less than 50 ppm each <br />Chloride report <br />® >- <br />1 <br />z <br />a ta <br />3. Bentonite Slurry, General Specifications <br />U- <br />co <br />The initial bentonite slurry must be tested prior to placement in <br />` <br />LU 0 <br />the trench. The slurry may be mixed in high shear mixers or <br />� <br />mixed and hydrated in slurry hydration ponds. In general, a <br />u <br />minimum hydration time of 8 hours will allow the bentonite slurry <br />f <br />LL - <br />to meet all criteria. A minimum bentonite content of 6 percent in <br />the slurry by weight is required. <br />4. Bentonite Slurry Testing Specifications before Placement <br />Viscosity Measured w/ Marsh Funnel (API RP 138-1) less <br />than 40 sec <br />Density less than 64 pcf <br />Filtrate Loss less than 20 cm3 <br />pH 6.5 to 10 <br />The tests listed above should be run 1 or 2 times per shift and <br />at least once per batch of slurry. The slurry must be further <br />tested after placement in the trench. The tests conducted are for <br />viscosity, density, sand content, and pH. Two sets of tests per <br />shift at two locations in the trench (approximately 2 feet below <br />the slurry surface and 2 feet above the bottom of the trench) <br />are required. If the density of the slurry in the trench exceeds 85 <br />pcf the excess solids must be removed by desanding or the slurry <br />replaced with fresh slurry. The slurry level must be maintained at <br />least 3 feet above the ground water elevation and no more than <br />2 feet below the top of the working platform. <br />5. Bentonite Slurry Testing Specifications after Placement <br />Unit Weight 1.03 to 1.40 gm/cm3 <br />Sand Content ASTM D 4381-84(1993)e 10 to 20 percent by <br />volume <br />6. Soil—Bentonite Backfill Specifications <br />S—B backfill slump ASTM C 143 1 set per 100 cu. yds. <br />Slump 2-6 inches <br />S—B backfill gradation 1 set per 300 cu. yds. <br />Screen (US Standard) Percent by Dry Weight <br />3 inch 100 <br /># 4 40-80 <br />#40 25-60 <br />#200 20-40 <br />Minimum Plasticity Index of 10 <br />7. Key Trench and Slurry Wall Cap Specifications <br />During excavation, soundings should be obtained to determine the <br />elevations of the top of the key layer, the bottom of the <br />excavation, and the bottom of the trench prior to backfilling. If <br />sediments in excess of 2 inches have accumulated it is necessary <br />to clean the trench bottom by airlift pumps or excavation <br />equipment to remove the sand and sediment that has settled. The <br />trench bottom should be cleaned, as a minimum, at the beginning <br />of each shift. Soundings should be obtained approximately every <br />20 feet. <br />Adequate keying in the S—B backfill to an impermeable layer at <br />the base of the wall will be required and specified in the final <br />design report for the slurry wall. The design documents will include <br />a description of the key in layer and describe how trench cuttings <br />or other observations will be used to assure that the slurry wall <br />will be adequately keyed. Temporary slurry wall protection will be <br />required in the form of a noncompacted soil cover placed within <br />one day over each backfilled 100 foot reach. The temporary cover <br />is removed after settlement (approximately 2 weeks) and replaced <br />with a compacted clay cover over the completed slurry wall. <br />8. Post Construction Testing <br />Post construction testing will be conducted in accordance with the <br />"Colorado State Engineer's Office." <br />9. Above specifications (notes 1-8) are provided as a general <br />guideline for permitting purposes. Final specifications and design <br />criteria will be developed during the final design of the slurry wall. <br />r� <br />,n <br />MC <br />X <br />,W <br />N <br />N <br />Qi CD <br />t/)(0°0E <br />00 o v <br />M <br />N O t� <br />�U„ <br />Q0 <br />N =. <br />CD � <br />J <br />LO <br />0 0 °° � <br />LL M <br />M a <br />0 <br />z <br />C <br />CIO <br />CO <br />tU <br />C <br />0 <br />E <br />cz <br />U <br />O <br />N <br />■ <br />4 <br />BIIIIIII <br />0 <br />monsoons <br />