防渗墙深度对闸坝深厚透水层渗流特性的影响

针对某大（2）型水库闸坝高、坝基覆盖层厚且发育5层极强透水层的问题，拟采用垂直防渗墙技术防渗。对此，利用三维有限元数值计算方法，分析了不同悬挂式防渗墙深度及封闭式防渗墙的防渗效果。结果表明，同一压力水头在防渗墙后骤降，防渗墙深度越大其降幅越大，至封闭式防渗墙时达到最大值；防渗墙后，坝基、闸基扬压力突降并趋于平缓；随防渗墙深度增加，下游坡脚的水力坡降下降，至封闭式防渗墙时水力坡降降至最小；随着悬挂式防渗墙深度的加大，坝基渗流量逐渐减小，至封闭式防渗墙时渗流量降至最小。

Impact of Cutoff Wall Depth on Seepage Characteristics of Thick Permeable Layers of Gate Dam

To solve the problems of high gate dam, thick overburden layers and 5 strong permeable layers of certain reservoir, the perpendicular cutoff wall technology is ready to be performed in the project. Three-dimensional FEM is performed to analyze the seepage control effects of the suspended cutoff wall of different depths and the closed cutoff wall. The results demonstrate that water head contours drop down more sharply after the cutoff wall with deeper cutoff wall, and retain the maximum at the closed cutoff wall; the uplift pressure at the dam base and the gate base decreases obviously after the cutoff wall, and becomes relatively flat afterwards; with the increase of the depth of the cutoff wall, the hydraulic gradient at the downstream slope toe decreases consequently, and retain the minimum at the closed cutoff wall; with the increase of the depth of the suspended cutoff wall, the amount of leakage at the dam base decreases, and retain the minimum at the closed cutoff wall.