中文摘要：

物质点法（MPM）属于一种无网格数值计算方法,它可导入各种土体本构模型,考虑土体流固耦合行为,能够有效模拟土质滑坡大变形及超大变形。本文介绍了物质点法基本原理、控制方程与求解格式;基于5种物质点法的多孔介质表征模型,简要回顾了土质滑坡运动全过程物质点法模拟的最新研究进展。采用单套单相物质点模型,对深圳＂12·20＂人工堆填土滑坡全过程进行了物质点法模拟,使用了线性加载方式确定初始应力场,并使用了Drucker-Prager屈服准则弹塑性本构模型、GIMP算法与MUSL求解格式。模拟结果表明,该边坡发生失稳后,最大滑距达510m,滑坡范围纵向间距为1050m,最小滑坡角5.95°,均与观测结果相吻合。土体内部等效塑性应变区的演化趋势显示,滑坡机制为渐进式破坏,具体表现为：坡趾土体首先沿基岩界面发生剪切破坏,随后坡顶出现拉张裂隙,坡趾与坡顶塑性区分别沿基岩界面向坡体内部发育,形成贯通滑动面后滑动加速,超大变形出现。物质点法模拟滑坡运动全过程有助于理解滑坡致灾行为,可为滑坡防治提供参考。

英文摘要：

Material Point Method（ MPM） belongs to one of the meshless numerical analysis methods. It is able to integrate a variety of constitutive models and consider the fluid-solid coupling behavior within soils,so as to effectively simulate the large and extra-large deformation of landslides. This paper introduces the fundamental principles of MPM,the governing equations and the solving formats. Based on the 5 types of porous media characterization models of MPM,we briefly review the state-of-the-art of run-out process simulation of soil landslides using MPM.Subsequently,we simulate the run-out process of Shenzhen ＂12·20＂landfill landslide using MPM with the single-layer and sing-phase material point model. Linear loading is applied to identify the initial stress field.Elasto-palstic constitutive models using Drucker-Prager yield criterion,GIMP algorithm and MUSL solving format are also used,respectively. The simulation results show that the maximal sliding distance reaches 510 m,after the slope losing its stability. Moreover,the longitudinal distance of the landslide scope is 1050 m and the minimal landslide angle is 5. 95°,both agreeing well with the observed results. The evolution trends of the equivalent plastic strain zone within the soil exhibit that the landslide mechanism is progressive failure. Specifically,shear failure ofthe soil occurs at the slope toe initially,and tensile fracture occurs at the slope top subsequently,with both plastic zones extending toward the interior of the slope along the bedrock. The extra-large deformation occurs once the sliding surface is cut-through to accelerate the sliding. The MPM simulation for the run-out process of landslides can shed light on the hazardous behaviors of landslides and provide assistants for landslide prevention.