基于率相关土水特征曲线的边坡稳定性分析

Slope Stability Analysis Based on Rate-dependent Soil-water Characteristic Curve

现有的非饱和土边坡稳定分析所采用的SWCC模型大多是基于平衡条件得到,但SWCC具有明显的率效应,即不同的饱和度变化率所得到的曲线并不重合,因此有必要考虑这种率效应对边坡稳定的影响。基于现有的率相关SWCC模型,得到了率相关条件下土体的抗剪强度准则,采用Bishop条分法推导了率效应影响的边坡安全系数计算公式。对比分析了基于率相关和率无关SWCC条件下边坡安全系数。结果表明:随着降雨强度、降雨持续时间的增大,安全系数不断下降,且考虑率效应以后的安全系数要更小。

Most of the existing SWCC models used for unsaturated soil slope stability analysis are established based on the equilibrium conditions. However, SWCC is obviously rate-dependent, which means that the curves obtained with different saturation change rates do not coincide. Such rate-dependent effect on slope stability should be considered.Based on current rate-dependent SWCC model, the shear strength criterion of soil mass under rate-dependent condition is obtained, and the calculation formula of slope safety factor under rate-dependent effect is derived by using Bishop slice method. The slope safety factors calculated based on rate-dependent condition and rate-independent SWCC are compared and analyzed. Results show that the safety factor decreases with the increase of rainfall intensity and rainfall duration, and the safety factor is smaller under rate-dependent condition.