岩体开挖卸荷后边坡失稳判据研究  

Study on Slope Failure Criteria of Rock Mass after Excavation and Unloading

作　　者：黄秋枫[1] 李建林[1] 

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002

出　　处：《水力发电》2008年第2期13-16,共4页Water Power

基　　金：国家自然科学基金项目(50379023);湖北省高等学校优秀中青年科技团体计划赞助项目(鄂教科[2004]7号)

摘　　要：岩体开挖是一个不断卸荷、变形损伤、质量劣化的动态力学过程。只有考虑岩体开挖卸荷过程才能较真实地模拟实际边坡因开挖而达到的位移场和应力场状态。如何根据有限元计算结果来判别边坡稳定性,是边坡稳定分析的一个关键性问题。强度折减有限元法的失稳判据主要有3种:①以有限元解的收敛性判定失稳状态;②根据计算域内最大节点位移与折减系数之间关系曲线变化特征判定失稳状态;③通过计算域内塑性区是否贯通判定失稳状态。结合岩体开挖卸荷后力学参数变化和3种失稳判据综合判定了实际边坡的稳定性,对一般边坡工程有一定的指导作用。The rock mass excavation is a continuous dynamic mechanic process which including unloading, damaged deformation and quality deterioration. Once considering the excavation and unloading process of rock mass, we can simulate the displacement field and stress field of rule slope resulted in excavation and unloading. How to judge the calculated slope＇s states, stability or instability, is a key problem for shear strength reduction methods. There are three failure criterias of shear strength reduction method using FEM. The instability state is judged by the convergence of equation＇s solution in the first criteria. The curve which expresses the relationship of node largest displacement with reduction coefficient is the judgment of the second criteria. The judgment of the third criteria is the connectivity of plastic flag. The paper expresses how to judge the stability of rock slope combining the changes of mechanic parameters after excavation and the three failure criterias. And it has some guiding effects and application value for the common slope.

关 键 词：开挖卸荷 稳定性分析 强度折减系数 失稳判据 岩质边坡 

分 类 号：O317[理学—一般力学与力学基础]