Laserfiche WebLink
3.5 BACKFILL PLACEMENT <br /> A. The backfill shall be placed continuously from the beginning of the trench,in the direction of the <br /> excavation,to the end of the trench.The advancing toe of backfill shall be within reach of the trench <br /> excavator at all times such that the trench bottom can be cleaned in accordance with Section 3.3.A <br /> above. Excavation must permit inspection and measurement immediately after completion and prior to <br /> backfilling. Placing operations shall proceed in such fashion that the surface of the backfill below the <br /> slurry shall follow a reasonably smooth grade and shall not have hollows,which may trap pockets of <br /> slurry during subsequent backfilling.Free dropping of backfill material through the slurry will not be <br /> permitted.Initial backfill shall be placed by lowering it to the bottom with clamshell bucket or backhoe <br /> until the surface of the backfill rises above the surface of the slurry or by lead-in slope.Additional <br /> backfill may then be placed in such manner that the backfill enters the trench by sliding down the <br /> forward face of the previously placed backfill.To accomplish this,sufficient backfill shall be piled behind <br /> the crest of the existing backfill slope to cause a mudwave action e face of the backfill.The backfill <br /> shall not be dropped or deposited in any manner that will caus regation.The self-seeking slope is <br /> typically inclined at 5:1 to 10:1(horizontal:vertical).The toe ckfill slope shall extend to the <br /> bottom of the excavation trench,such that no more than of tre emains open between the toe <br /> of the backfill and the active excavation. <br /> B. An acceptable substitute for the initial placing of ill by use of a cla shell bucket may be a lead- <br /> in trench.The lead-in trench shall begin at a point 'd e limits of work and provide sufficient <br /> distance for the backfill face to form,by placing the b into the trench,before the toe of the backfill <br /> reaches the point where the cut-off is re he lea - ench shall be 1V:1H or flatter. <br /> 3.6 COLD WEATHER CONSTRUCTION REQUIREMEN <br /> A. No frozen backfill or slurry sh. - p . d in t oil-bentonite slurry wall trench.All ice forming on the <br /> surface of the slurry trenc . I be r; •ved p to the start of each shift.No frozen or frost bearing <br /> backfill material shall be p . • int, hen freezing temperatures exist the Engineer will <br /> conduct visual inspections of •rry in the trench and the soil-bentonite backfill.The inspection may <br /> include measure - e •ture if necessary to evaluate the potential for frozen material.The <br /> frequency oft inspecti• ill • minimum of once per day typically,early in the day prior to the <br /> placement of . •ackfill. Ad• •nal inspections may be required if conditions warrant or change. <br /> B. Slurry wall constru• wor eduled between November 1st and March 31st will require an <br /> additional section in ' k Plan Submittal detailing cold weather construction procedures. <br /> 3.7 TREATMENT FOR TOP OF BACKFILL <br /> A. Upon completion of slurry wall construction,a protective cap shall be constructed on top of the slurry <br /> wall as shown on the Contract Drawings. <br /> 3.8 CLEAN-UP <br /> A. After completion of the backfill and capping,all remaining excavated material and slurry shall be <br /> removed and the surface shall be cleaned and leveled as directed by the Engineer.Excess slurry shall be <br /> disposed by drying,mixing with dry materials or spreading in thin layers on adjacent areas designated by <br /> the Engineer. No slurry shall be left in ponds,and all ponds shall be pumped dry and backfilled in a <br /> manner approved by the Engineer. <br /> Loloff Slurry Wall 3156 00-8 <br />