脱湿速率对膨胀土堑坡稳定性的影响分析

以广西南宁膨胀土为研究对象,设置不同温湿度条件引起的脱湿环境,测试不同脱湿速率作用下,膨胀土的收缩特性以及持水能力,预测不同脱湿速率作用下非饱和土体渗透曲线,并对膨胀土边坡雨水入渗过程进行数值模拟计算。试验结果表明,脱湿速率越小,膨胀土收缩变形越大,这说明自然条件下湿度大的气候里,经过缓慢蒸发,表层土体的膨胀潜势会较大。数值计算结果表明,脱湿速率较小时,降雨后边坡雨水入渗的影响深度较大,这说明,湿度大的气候条件下,长期的蒸发过程,会导致更大的降雨入渗深度,从而不利于膨胀土边坡的稳定。

Influence of different drying rates on stability of cut slope of expansive soils

For the expansive soils of Nanning in Guangxi province of China different drying environments are acquired to test the shrinking characteristics and water retention by setting different temperature and humidity conditions. The unsaturated permeability curves under different drying rate are predicted. The infiltrating process of cut slope is numerically simulated. The test results show that the slow drying rate produce a large shrinking deformation. The sustainable evaporation with high humidity results in a large potential swelling deformation in shallow strata. The numerical computation indicates that an evaporation process of slow drying rate produces a large infiltration depth. It is concluded that the sustainable evaporation with high humidity induces a large infiltration depth, which is adverse to the stability of cut slope of expansive soils.