基于重力增加法的边坡失稳破坏全过程模拟

Simulation of the Whole Process of Slope Failure Based on Gravity Increase Method

边坡失稳破坏是渐进积累的过程,采用基于重力增加法的连续-离散耦合分析方法弥补了传统边坡稳定分析方法无法反映边坡岩体启动-滑动-堆积的渐进破坏全过程的缺陷。以红石岩边坡工程为实例,在边坡模型的表层岩体中引入界面单元,建立连续-离散耦合的边坡计算模型,模拟边坡临界破坏状态,得到安全系数和滑裂面,并将计算结果与刚体极限平衡法的分析结果进行对比。通过增加重力加速度,获得边坡失稳破坏的渐进破坏全过程。结果表明:2种方法得到的安全系数一致,最危险滑裂面的位置和形状基本吻合,证明基于重力增加法的连续-离散耦合分析方法用于边坡失稳破坏具有可行性。极限平衡法仅用于分析临界失稳状态,不能预测后续滑块的形成,而连续-离散耦合分析方法能进一步模拟边坡临界失稳状态后的边坡破坏全过程,为边坡治理提供有效参考。

Traditional slope stability analysis methods could not reflect the whole process of progressive failure from crack initiation,sliding,to piling up.In view of this,a combined finite-discrete element method based on gravity increase method(FDEM-GIM)is proposed to study the slope failure of Red Rock Landslide in Yunnan Province of China.Interface elements are introduced into the surface rock mass of the slope model to build the combined finite-discrete slope model and simulate the critical failure state of slope.The safety factor and the sliding surfaces of the slope are acquired,and then are compared with those obtained by rigid body limit equilibrium method.By increasing the gravity continuously,the progressive failure process of the slope is obtained.The results demonstrate that the proposed FDEM-GIM is feasible in slope stability analysis because the safety factor,the position and shape of the most dangerous sliding face obtained by FDEM-GIM are consistent with those by rigid body limit equilibrium method.Moreover,rigid body limit equilibrium is only suitable for the critical instability state of slope as it could not predict the formation of subsequent sliding blocks,while the proposed FDEM-GIM could further simulate the whole process of slope failure.