岩桥破坏的简化模型及在节理岩体模拟网络中的应用

提出一个简化的岩桥破坏 /结构面扩展模型 ,该模型符合现有试验观测成果 ,在力学机理上基于Lajtai对岩桥剪切破坏的研究 ,能方便地计算实际问题中各种结构面组合情况下的抗剪力。利用先进的优化方法 ,该模型用于在结构面模拟网络中搜索抗剪力最小的结构面-岩桥组合 ,从而研究裂隙岩体的结构面连通特性和综合抗剪强度。算例和分析表明 ,在不同的法向应力作用下 ,岩体沿某一组结构面受剪时 ,破坏路径上的连通率为常数 ,这时可以使用连通率求取岩体的综合抗剪强度指标。在剪切方向与某一组结构面的平均延展方向不相同时 ,破坏路径上的连通率随法向应力的改变而改变 ,这种情况下岩体的综合抗剪强度只能通过模拟试验直接求得。

A simplified discontinuity propagation model and its application in mechanics of rock mass

This paper introduces a simplified rock bridge failure model based on the Lajtai's theory. The model can explain what has been observed in the tests. The shear strength of a rock bridge under various joint combinations can be readily determined using this model. In a simulated joint map, modern optimization methods are used to determine the comprehensive shear strength contributed by the rock bridge and joint combination that offers the least resistance along a specified direction of enforced shear. Shear strength parameters are subsequently summarized using this numerical modeling test by applying a number of normal force.It has been found that this approach is better than the conventional one that employs a single criterion of the joint persistence ratio to find the strength parameters.