ISSN 1000-3665 CN 11-2202/P

    堆载诱发型土质滑坡运动特征物质点法模拟

    Run-out characteristic simulation of a surcharge-induced soil landslide using the material point method

    • 摘要: 坡顶堆载是人类工程活动诱发滑坡的主因之一。物质点法(MPM)属于一种无网格数值计算方法,它能够有效模拟滑坡大变形全过程物质行为与运动特征。文章基于线性形函数离散方法、MUSL求解格式及Drucker-Prager屈服准则,建立了可用于滑坡全过程模拟的单套单相物质点模型;通过对比干燥铝棒堆积物模拟砂堆失稳过程的基准试验结果,对模型有效性进行了验证。对堆载诱发型土质滑坡典型工况进行了物质点法全过程模拟,获得了滑坡全过程中典型时刻坡体形态、塑性应变分布以及控制点滑速演化趋势。结果表明:算例堆载诱发型土质滑坡属推移型滑坡,具有渐进性破坏特征,可分为坡顶压缩、局部蠕滑、加速滑动与减速滑动等四个阶段。参数分析结果亦表明,堆载诱发型土质滑坡前缘物质运动特征量均与堆载量间存在强正相关性、而与土体黏聚力及内摩擦角存在强负相关性。统计29种典型工况,分别建立了峰值滑动加速度、最大滑速、最大滑距及坡体最大动能等运动特征量与堆载量、土体黏聚力及内摩擦角之间的线性回归方程,可用于堆载诱发型土质滑坡致灾行为预测。

       

      Abstract: Spoil ground surcharge is one of the main factors inducing landslides in hilly grounds triggered by human engineering activities. The material point method (MPM) belongs to one of the meshless numerical analysis method, which can effectively simulate the material behavior and the run-out characteristics of landslides. Based on the discrete method using the linear shape function, the MUSL solving format and the Drucker-Prager yield criterion, we develop a single-layer and single-phase MPM model to simulate the run-out process of landslides. In comparison with the benchmark experiment results of the process of a sand pile losing its stability and simulated with accumulated dry aluminum bars, the proposed MPM model is verified. The run-out process of the typical scenario of the surcharged-induced soil landslide is simulated using MPM. The related results during the representative moments of the run-out process, including the morphology of slope mass, the plastic strain distribution and sliding velocity evolution trends of reference points, are obtained. The results of the numerical example show that the surcharge-induced soil landslide belongs to the thrust-type landslide, and is of the progressive failure. The whole run-out process can be divided into 4 stages, namely, the slope crest compression, local creep sliding, accelerated sliding and decelerated sliding. Concerning the sliding front, the results of parametric analysis also show that a strong positive correlation property exists between both of the kinetic representative parameters and the surcharge amount, and a strong negative correlation property exits between the kinetic representative parameters and the cohesion or internal friction angle of the soil. It is noted that the kinetic representative parameters include the maximal sliding acceleration, velocity, distance and kinetic energy of the slope mass. Based on 29 typical scenarios, the linear regression equations of all of the above 4 kinetic representative parameters, denoted by the surcharge amount, cohesion and internal friction angel of the soil, are established to predict the disastrous behavior of the surcharge-induced soil landslides.

       

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