滑坡负压排水方法的试验研究

Experimental study on negative pressure drainage of landslide

及时迅速地排出坡体地下水能够有效地减少降雨引发的滑坡灾害。目前常用的仰斜式排水法因是重力排水,易在孔内产生淤堵而造成其长期稳定性不能得到保证。而利用俯倾排水孔进行负压排水,因其排水速度快,则不会产生孔内淤堵问题,但负压排水过程中,其贮水空腔周边岩土体可能因负压作用导致透水性变差,而其过滤装置也可能因负压的存在更容易淤堵。为了验证负压排水对土体产生的压密效果,并研究解决或减轻包裹贮水空腔的过滤装置的淤堵问题,对负压排水方法进行物理模型试验研究。结果表明:(1)排水形成的负压对土体有明显的压密效果,较大程度降低了土体的孔隙率及渗透性,但在任何密实度条件下,负压排水始终比渗流排水更快;(2)采用透水性能良好并有一定抗压力的材料包裹贮水空腔,可有效提升过滤装置的抗淤堵能力。

Timely and rapid drain of groundwater from slope can effectively reduce landslide disasters caused by rainfall.At present,the common inclined drainage method is gravity drainage,which is easy to cause siltclogging in the hole,so its long-term stability can not be guaranteed.If the negative pressure drainage with fast drainage speedis carried out by using the downdip drainage hole,there will be no problem of silt clogging in the hole.However,in the-process of negative pressure drainage,the permeability of rock and soil around the water storage cavity may become worse because of negative pressure,and the filtration device may be easier to be clogged because of the existence of negative pressure.In order to verify the compaction effect of negative pressure drainage on soil and to solve or alleviate the silt cloggingproblem of filtration device wrapped around the water storage cavity,the physical model test of negative pressure drainage method is carried out.The experimental results show that:(1)The negative pressure formed by the drainage has obvious compaction effect on the soil body,and the porosity and the permeability of the soil body are greatly reduced.However,under any denseness condition,the negative pressure drainage is always faster than the seepage drainage.(2)The water storage cavity is wrapped with materials with good permeability and certain pressure resistance,which can effectively improve the anti-silting ability of the filtration device.