悬挂式防渗墙对不同细料含量堤基管涌的影响

Experimental Study on the Impacts of Suspended Cut-off Wall in Embankment Piping Under Different Contents of the Fine Particles

在有悬挂式防渗墙的情况下,细颗粒含量不同的堤基,管涌的发展情况和破坏形式不同。利用室内砂槽试验,通过改变堤基的细颗粒含量,对含有悬挂式防渗墙的双层堤基管涌破坏过程进行了模拟,研究了防渗墙对细颗粒含量不同的3种堤基管涌破坏形式和发展机理的影响。试验结果表明:细颗粒含量为26%时,临界水力梯度较大,但是发生管涌后,流量和涌砂量较大,管涌发展速度较快,且管涌通道主要发生于砂砾石层顶面,破坏程度逐渐提高,容易产生较大的渗透变形,造成堤基上部黏土层的坍塌,对工程的危害较大;细颗粒含量小于23%时,管涌发展逐渐从砂砾石层顶面转为砂砾层内部,管涌时细颗粒在土体孔隙中流动,对土骨架的影响较小,管涌发展速度较慢,对堤基的危害程度较低。

The situation of development and destruction forms of piping is different, because of different fine particle contents with the suspended cut-off wall. By means of laboratory test, through changing the flue content of embankment, the destruction process of piping of the double-layer embankment with the suspended cut-off wall were simulated and the impact of the suspended cut-off wall on the ernbankment piping destruction form with different fine particle contents and development mechanism was studied. The test results show that when the fine panicle content is 26%, the critical hydraulic gradient is higher, once the piping occurs, flow rate and the erosion mass are larger, the speed of piping is quicker, and the piping channel mainly along the top of the gravel layer, the extent of damage gradually increases, prone to large seepage deformation, which leads to the collapse of the upper embankment, great harm to the embankment ; when the fine panicle content is less than 23%, the development of embankment piping flom the top of the gravel layer is gradually turned into the internal sand, the fine particle flow in soil pores when piping, which has little effect on the soil skeleton, piping development speed is relatively slower and less harmful to the embankment.