| 摘要 |
<p>ENVIRONMENTAL CUT-OFF FOR DEEP EXCAVATIONS High density polyethylene sheets are installed in panel forms to form an impervious barrier to fluid flow particularly corrosive contaminates and pollutants. A slit is excavated in the earth under a bentonite slurry to the required depth. A relatively thick, high density polyethylene sheet is placed in the trench and connected to two high density polyethylene pipes or channel members, the with of which, in the direction transverse to the direction of the wall, is the width of the trench. The panel length typically will be 15 to 30 feet. Once the high density polyethylene panel is installed, the slurry is displaced on both sides by a backfill material that can be a soil-bentonite, cement-bentonite or concrete. A secondary panel section intermediate two previously formed primary panels is made using a secondary panel of high density polyethylene similarly constructed but using smaller diameter pipe or channel members than the primary panel pipes. This panel is then lifted and the two smaller pipes or channels lowered into the primary panel pipes or channels with the high density polyethylene panel extending between through two slots or openings in facing primary panel pipe or channel elements. A non-shrinking grout is then pumped into the pipe connection to form a tight joint.</p> |
