降雨条件下土质滑坡全过程物质点法模拟研究

Rainfall infiltration is a key factor for slope stability. Due to its limitation in simulate large deformation, the finite element method (FEM) can be only used to analysis the failure stage (i.e. determine the failure surface and safety factor) rather than the post-failure stage of slope stability. Based on the recently developed Material Point Method(MPM), this research project presents a research on the numerical simulation of the failure and post-failure process of rainfall triggered landslides. The main research works include: (1) develops the formulation of a numerical procedure based on MPM experiencing large deformation, by considering the unsaturated conditions and fully coupled dynamic process in a deformable multi-phase porous medium, and the numerical implementation of the proposed MPM formulations into the coupledMPM++ code;(2) numerical simulation of the rainfall triggered landslides by the proposed MPM model, to study the failure mechanism and the mechanism of transition from rainfall-induced slide to flow at unsaturated condition, by performing parametric study, the sliding distance, sliding velocity, sliding acceleration and the final debris deposit shape will be studied;(3) the laboratory experimental study on the mechanism of failure and post-failure process of the rainfall triggered slope landslide.

降雨是诱发滑坡的重要原因，滑坡的破坏过程可以分为失稳阶段和破坏后阶段。目前降雨入渗条件下滑坡的理论和试验研究主要集中在失稳阶段，对于滑坡的全过程特别是破坏后阶段缺乏研究。本项目拟采用基于连续介质大变形理论的物质点法，对降雨条件下土质滑坡全过程进行模拟分析，主要研究内容包括：（1）建立考虑土体骨架和孔隙流体两套物质点的非饱和两相耦合物质点法计算模型；（2）开展降雨入渗滑坡全过程数值模拟，通过参数敏感性分析，对滑坡的变形演化规律和破坏后的运动和形态等进行研究；（3）开展室内模型试验，对模型试验进行数值模拟，验证数值模型的有效性；研究降雨条件下滑坡破坏后阶段的行为和形态及其变形演化规律；并评价边坡失稳后的破坏后果。本项目旨在通过数值模型开发、数值模拟及模型试验对降雨入渗诱发的土质滑坡灾害展开系统的研究，为模拟降雨条件下土质滑坡的全过程提供一种新的数值平台。

边坡失稳破坏滑坡是岩土工程钟最常见的灾害之一，滑坡的破坏过程可以分为失稳阶段和破坏后阶段。目前滑坡的理论和试验研究主要集中在失稳阶段，对于滑坡的全过程特别是破坏后阶段缺乏研究。本项目拟采用基于连续介质大变形理论的物质点法，对土质边坡失稳滑坡全过程进行模拟分析，主要研究内容包括： （1）开发了并行物质点程序，测试了并行程序加速比。（2）开展了滑坡全过程数值模拟，阐明了边坡失稳机制及破坏后的演化规律。（3）建立了随机物质点法并使用随机物质点法对边坡滑坡过程进行了模拟。（4）建立了耦合物质点理论模型，开发了耦合物质点法模拟程序coupledMPM++。（5）对B-bar算法在广义插值物质点法中的应用进行了研究并给出了实现方法。本项目旨在通过上述研究来从根本上揭示边坡大变形破全过程的破坏厚国及致灾机理，为模拟土质滑坡的全过程提供一种新的数值平台。