均质土坡渐进性破坏分析及变分法验证

Study on Progressive Failure for Soil Slope and Variational Method Validation

采用有限元软件ABAQUS构建了均质土坡二维有限元分析模型,动态模拟了土坡的塑性区发展及其渐进破坏过程,自动搜索出潜在滑动面.以变分法为基础,研究平面应变状态下边坡稳定的平衡方程,求解出最危险滑动面的函数表达式,并与数值模拟结果进行了对比验证.研究结果表明:随着折减系数Fr的不断增加,土坡自稳能力不断降低,破损区域不断发展延伸,当破裂面完全贯通时,边坡接近极限破坏状态,完成渐进性破坏.由强度折减法确定的土坡最危险滑裂面与采用变分法计算的解析结果趋势大致相同,均为圆弧形滑裂面.

Based on the finite element program ABAQUS,the 2D finite element numerical model of homogeneous soil slope was established and analyzed. The development and gradual failure process of the plastic zone for the soil slope were simulated dynamically. The potential sliding surface was searched automatically. Based on the variation method,the balance equation of the stability for soil slope was analyzed under the plane strain state.The most dangerous sliding surface function expression was solved. Finally,it was compared with the results of numerical simulation for validation. The results show that with the increase of test reduction factor Fr,the soil stabilizing ability reduced,and the slope damage area expanded. When the slope is well versed in the damaged area,it is close to the limit state of instability,and the gradual damage of slope become finish. The most dangerous slip surface was analyzed by the strength subtraction and it is roughly the same as the result of variation method： they are all critical circular slip surface.