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BACKFILL EXISTING <br />TRENCH WITH NATIVE <br />MATERIALS <br />• <br />V <br />N <br />N <br />�~ (0 000 <br />00 C) O <br />a) M <br />rA a)U I= <br />L� <br />O ¢ 0 N U <br />SLURRY WALL NOTES: J <br />1. Bentonite Specifications [■■I 0 A � <br />YP/PV ratio API Std. 13A less than 3 0� o LL o <br />Viscometer greater than 30 I■' co <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 SDecifications <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 />2; 3. Bentonite Slurry General Specifications <br />° e The initial bentonite slurry must be tested prior to placement in <br />a a (MIN) the trench. The slurry may be mixed in high shear mixers or <br />mixed and hydrated in slurry hydration ponds. In general, a L6 <br />° a. a minimum hydration time of 8 hours will allow the bentonite slurry <br />ASTM C33 ° to meet all criteria. A minimum bentonite content of 6 percent in <br />CONCRETE SAND the slurry by weight is required. <br />(IF REQUIRED) . <br />VAIESa 4 4.0' 4. Bentonite Slurry Testing Specifications before Placement = <br />SAND AND GRAVEL Viscosity Measured w/ Marsh Funnel (API RP 1313-1) less <br />ALLUVIUM than 40 sec W <br />Density less than 64 pcf <br />.05' Filtrate Loss less than 20 cm3 <br />1.5 °(TYP.) d , .::: ,: (TYP.) pH 6.5 to 10 <br />TYP. <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 />3' 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 />4t are required. If the density of the slurry in the trench exceeds 85 <br />PERIMETER DRAIN DETAIL (TYPICAL SECTION IF REQUIRED) pcf the excess solids must be removed sa the slurry = <br />replaced with fresh slurry. The slurry levell must <br />be st be maintained <br />tained at 4) <br />least 3 feet above the ground water elevation and no more than <br />2 feet below the top of the working platform. H <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)e10 to 20 percent by <br />volume 3 i <br />O <br />6. Soil—Bentonite Backfill Specifications i an <br />S—B backfill slump ASTM C 143 1 set per 100 cu. yds. a i <br />Slump 2-6 inches i <br />4) <br />19 <br />S—B backfill gradation 1 set per 300 cu. yds. O <br />i <br />Screen (US Standard) Percent by Dry Weight m <br />3 inch 100 <br /># 4 40-80 <br />#40 25-60 <br />#200 20-40 77 <br />I� <br />VARIES <br />Date <br />a- <br />a <br />0 <br />z <br />JT -Derr <br />Scale <br />25' <br />dol <br />3d3 <br />ry <br />w-� <br />a-:2 <br />aY J <br />O (i_I <br />=)J <br />a-a <br />V) 3: <br />OVERBURDEN AND TOPSOIL <br />BACKFILL ALL DISTURBED AREAS <br />DOWN TO WATER SURFACE <br />WATER SURFACE <br />TYPICAL BACKFILL SECTION <br />N.T.S. <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 Testina <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 />U <br />m <br />m <br />cu <br />0 <br />0 <br />Z <br />U) <br />N <br />O <br />70 <br />C <br />W <br />O <br />cz <br />_Cz <br />U <br />N <br />Ir <br />N <br />r <br />O <br />O <br />N <br />■ <br />J&T Consulting, Inc. <br />4�7,. <br />?�.� <br />Job # <br />Date <br />Drawn B <br />Designed B <br />Checked B <br />File <br />JT -Derr <br />Scale <br />Sheet: <br />3d3 <br />