滑带土抗剪强度指标确定的数值计算方法

Numerical Method for the Determination of Shear Strength Parameters of the Slip Zone

介绍了滑带土反算法的基本原理,采用有限差分法平面应变模型,对某一处于临界稳定状态公路边坡的抗剪强度指标进行反算,分别取与滑坡主轴距离相等的两断面,先假定其中一抗剪强度指标c(或φ)已知,反复试算和调整另一指标φ(或c),直到程序计算所得安全系数K=1为止,得到一组相对应的抗剪强度指标,按相同方法重复试算几次,得到相对应的c、φ值,然后把两断面的数据绘在同一坐标系中,其交点即为该坡体的抗剪强度指标。分析表明,采用数值模拟反算法计算滑带土的抗剪强度指标是可行的。

In this paper, the basic principles of the numerical back analysis of slip zone soil properties are introduced. The finite difference plane strain model is used to back predict the shear strength parameters of a highway slope in the critical stability conditions. Two sections with the same distance from the main axis of the landslide are taken respectively. First, one set of the shear strength parameters c(or φ) is assumed, and the other set of parameters φ(or c) is repeatedly tested and adjusted until the numerical analysis reaches critical state. At the critical condition, factor of safety K=1 is assumed, a set of corresponding shear strength parameters is obtained. Several groups of corresponding c and φ values are analyzed repeatedly using the same method. Then the data of two sections are plotted in the same coordinate system, and the intersection point is the shear strength parameters of the slope. The results show that it is feasible to estimate the shear strength parameters in the sliding zone soil by the back analysis using the numerical simulation method.