以宁夏海原县九彩乡滑坡为例,通过对其工程地质特性进行调查,得出了滑坡成因.通过实验得出黄土与滑带土在静力状态与动力状态下的力学强度参数,然后运用FLAC3D有限差分软件建立了斜坡数值分析模型,加入震级与海原大地震相近的汶川地震的地震荷载,分析泥岩上覆的薄层黄土滑坡在地震作用下的破化模式.在模拟过程中可以得出:①在地震荷载的作用下,斜坡水平位移最大处发生在坡体后部较陡的部位,坡体中部和坡脚处的位移相对较小;②根据最大剪应变云图与监测点位移图,斜坡的大变形主要发生在地震加载的5～ 10s的区间内,10s后的变形趋于稳定.%Taking Jiucai landslide of Haiyuan county as an example,we investigated its engineering geologic condition,then we unraveled the cause of landslide.Through experiment,we got the strength parameters of loess and slip soil in static and dynamic condition respectively,after which we built up slope-data-analysis model via FLAC3D software and input the earthquake load of Wenchuan earthquake whose load is similar with that of Haiyuan earthquake.We analyzed sliding mechanism of the thin loess slope on mud rock under earthquake load,and came to conclusion:①when earthquake happens,the maximum horizontal displacement is found in the cliff part in slope,while horizontal displacement in middle part and base of slope is smaller.②according to cloud pictures of shear strain and displacement diagram of monitoring points,maximum displacement of slope happens in the first 5th to 10th second after imposition of earthquake load,and displacement of slope become stable after 10th second.
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