应变软化边坡稳定性分析方法研究

对于具有应变软化特性的岩土质边坡,如果按照峰值强度进行设计与分析,会遗留安全隐患;如果取残余强度分析,则会增加工程成本,造成不必要的浪费。因此考虑应变软化的边坡稳定性分析方法对于此类边坡的评价与治理具有重大的意义。首先基于岩土体的应变软化本构借助FLAC软件实现了边坡的渐进性破坏过程模拟;其次基于最大剪应变增量确定了边坡的滑面;基于滑面上强度参数的时空分布规律借助Matlab软件平台实现了基于矢量和法的应变软化边坡稳定性分析;然后基于材料参数沿滑面的空间分布规律提取了等效黏聚力和等效内摩擦角,并借助极限平衡法分析了边坡在渐进性破坏过程中滑面及安全系数的变化过程,用于补充上一种方法在坡体未产生明显破坏时的不足;最后将两种不同的应变软化边坡稳定性分析方法对应计算结果进行对比分析,验证了两种方法的合理性及可靠性,同时两种方法形成相应的互补关系,很好地解决了应变软化边坡稳定性的分析问题。

Stability analysis methods for strain-softening slopes

Designing and analyzing the rock-soil slope with strain-softening behaviors according to the peak strength tends to cause potential safety hazards, while that according to the residual strength tends to increase costs. The stability analysis methods for slopes considering strain-softening behaviors are of great significance. Based on the strain-softening constitutive relation, the progressive destruction of a slope is simulated in FLAC first. Then the slip surface is determined by the maximum shear strain increment. The vector sum method for stability analysis of the strain-softening slope is accomplished by Matlab based on the temporal-spatial distribution of strength parameters on the slip surface. The equivalent cohesion and internal friction angle are extracted from the spatial distribution of strength parameters of the slip surface. The limit equilibrium method is implemented to analyze variation of the slip surface and safety factor during the progressive destruction to supplement the drawback of the vector sum method. The results of the two methods for the stability analysis of strain-softening slopes are compared, and their reasonability and reliability are validated. The two methods show a complementary relationship in solving the stability problem of strain-softening slopes.