膨胀土渠坡坡顶不同渗控防护方案的计算分析

Calculation and Analysis of Different Seepage Control Measures on the Top of Canal Slope for Expansive Soil

土体含水率的变化是膨胀土边坡发生破坏的重要原因。坡顶渗控防护可以防止或减少地表水在坡顶附近积聚和入渗,从而有效抑制坡体含水率的变化。对采用水泥改性土、砂垫层、表砂层和土工膜4种坡顶防护措施的渠坡分别进行了有限元分析,通过比较土体孔压在降雨蒸发循环后的变化来研究4种措施的防护效果并进行了对比分析,同时还研究了不同防护范围的效果差异。结果显示,水泥土和土工膜措施的防护效果较砂垫层和表砂层更好,坡顶防护范围越大,防护效果越好,但是防护范围超过10 m后,防护效果不再明显增加。

The change of soil water content is an important reason for slope failure of expansive soil. Seepage control measures on the top of slope can prevent the surface water fromaccumulating and infiltrating,so the change of water content in slope body can be reduced effectively. Canal slope with 4 different seepage control measures,including cement soil,sand cushion,surface sand and geomembrane,were calculated by FEM. The protection effect of 4 measures was researched and contrasted by analyzing the pore pressure in slope body after rainfall and e-vaporation. The effect of different protected ranges was researched as well. It is shown that, the measure of cement soil and geomembrane has a better protection effect than that of sand cushion and surface sand. Protected range is bigger and the protection effect is better. But protec-tion effect will not increase significantly when the protected range exceeds 10 m.