Typical pipeline trench cross section details with dewatering system this drawing available in autocad format.
to the work zone, installation can begin.
The operator will start the engine on the trencher, and will begin turning the chain.
The chain on the trencher has cutters that will do the digging. As the chain begins
turning the operator will begin lowering his boom into the ground. Once he has
started to lower his boom, the pipe will begin pulling itself into the ground.
After the chain boom is a few feet in the ground, the operator will then stop to allow
the excavator to pour stone into the stone chute, and then in the hopper as well. This
will allow stone to be placed into the cut right away. Now that the stone has been
placed into the chute, the operator of the trencher can begin lowering his boom into
the ground the rest of the way, keying into the weathered shale layer. As the boom
reaches the desired depth, the operator will begin tracking the machine away from
where it originally set in the ground. This will allow the pipe to pull itself into the
ground. This will continue until the trencher reaches the end of the system.
Meanwhile, an excavator will fill the stone hopper with 3/8" Class A washed stone
from a rock box being pulled by the excavator and continually filled by the front end
loader. The excavator will continue to feed the trenching equipment until the
machine reaches the end of the system. As the chain is turning in the ground it will
bring up the soils out of the ground and place them back over the trench, backfilling
the trench as it goes. Afier trench is compacted and graded to match existing ground,
some additional excavated materials will be left on top of the ground upon
completion, the materials will be stockpiled in a location that has positive drainage
toward the retention pond.
Pumping of Dewatering Systems -
After the system(s) is installed, a 4" Wellpoint Pumnp will be placed at the desired end
of the system(s) as per figure 5 and 8 in RECON's Work Plan. A short solid pipe will
be coupled to the end of the system to allow it to reach the pump. After the temporary
holding tanks are constructed the pump(s) will then be started up with the vacuum
relief valve open (to allow slow build up of vacuum so the sock does not get plugged
up). The contractor will then let the system pump for as long as desired before
excavation. Water levels will be checked periodically through the existing
piezometers/wells to monitor ground water levels.
Breakdown and Loading of MTLLC Trencher -