| 摘要 |
<p>Plastic linings for ponds or reservoirs are provided with flanged openings in the base which can accept an extensible buoyant standpipe for relieving subterranean hydrostatic pressures. The pipe may be a flexible plastic tube with a wire-reinforced hooped or helical structure which is longitudinally extensible to adapt to variations in the depth of water above the base of the lining. The upper end of the pipe is fitted with a buoyant collar, opt. tethered to limit lateral drift, opt. incorporating a submersible pump. Vents are regular intervals are more reliable for venting the ground beneath the lining than long drains extending to the borders of the reservoir and which are prone to blockage.</p> |
