基于颗粒元模拟的含软弱夹层类土质边坡变形破坏过程分析

Analysis of failure process of similar soil slope with weak intercalated layer based on particle flow simulation

采用基于离散单元法的颗粒元程序,引用平行连接模型,通过数值试验,确定土体细观参数与宏观力学性质的关系,并据此建立含软弱夹层的类土质边坡模型。通过路堑开挖卸荷过程模拟,再现了大变形条件下坡体渐进性破坏的完整过程,并对裂隙的发展演化过程进行实时监测。模拟结果显示,含软弱夹层类土质边坡的破坏过程历经裂隙的形成、扩大、发展直至贯通,最终发生大规模滑移破坏;裂隙从滑坡体前缘和软弱层面开始,范围逐步扩大,呈现典型的类土质边坡的渐进性破坏形式;滑坡发生后,土体结构破坏严重,承载能力大幅下降。边坡滑移过程模拟和最终滑移结果与现场滑坡状况完全吻合,表明该方法适用于类土质边坡变形破坏过程分析及其机理研究。

Based on the theory of particle flow code （PFC）, one of the discrete element methods, a series of biaxial tests are simulated to establish the relationship between micro parameters and macro mechanical properties. A numerical model of similar soil slope with weak intercalated layer is constituted by adopting the parallel-bond model of PFC. The progressive failure process of slope is simulated and fissures in slope are monitored during excavation. The simulation results show that the failure experiences a process of fissures formed, grew lager, and developed until large scale landslide occurs. The fissures form from the toe of the slope and weak intercalated layer at first, then expanded until slide occurs, which behaves as a typical progressive failure process; soil structure is seriously damaged and bearing capacity decline after slide occurs. The simulated failure process and numerical results fit the site condition well. It is shown that the proposed method can be used to study the similar soil slope＇s failure process and its mechanism.