基于三维离散元的弃渣边坡变形过程模拟

以某隧道弃渣边坡为研究对象，采用野外调查、室内试验等方法对弃渣体的力学参数和坡体结构特征进行测定与分析，利用三维离散元软件 PFC3D 对弃渣边坡变形至滑动过程进行数值模拟。结果表明：(1)弃渣体由几乎无黏结的碎石块组成，运用线性模型能够符合实际情况。采用筛分测定的级配与概化形状后生成的颗粒簇模拟弃渣碎石较为合理。(2)弃渣边坡下部的碎石位移增加最快，上部的碎石位移次之。边坡的变形范围从坡体下部与上部向坡体中部扩张，变形区域在中部连为一体。坡表开始滑动时，弃渣边坡变形区域与地面的夹角约等于弃渣碎石自然休止角。(3)变形区分界面发生“台阶-圆弧-台阶-圆弧”的变化并向坡内扩展，在此过程中坡体表面碎石的位移最先达到失稳临界点，失稳时碎石顺着坡面逐层滑动。

Simulation Study on Slope Deformation Process of Waste Slag Dump Based on Three Dimensional Discrete Element

Taking a tunnel slag slope as the research object, the mechanical parameters of the slag body and the structural characteristics of the slope body are measured and analyzed by means of field investigation and laboratory test, and the deformation and sliding process of the slag slope is numerically simulated by using the three-dimensional discrete element software PFC3D.The results show that :(1) The discarded slag body is composed of almost unbonded gravel, and the linear model can be applied to the actual situation. It is more reasonable to simulate waste residue and gravel by particle cluster generated by sieving gradation and generalized shape. (2) The gravel displacement at the lower part of the abandoned slag slope increases the fastest, followed by the gravel displacement at the upper part. The deformation range of the slope extends from the lower part and the upper part to the middle part of the slope, and the deformation area is connected in the middle part. When the slope surface begins to slide, the angle between the deformation area of the abandoned slag slope and the ground is approximately equal to the natural repose angle of the abandoned slag gravel. (3) The interface of deformation zone changes from step-arc-step-arc to step-arc and extends to the slope. In this process, the displacement of gravel on the slope surface reaches the critical point of instability first, and the gravel slides along the slope layer by layer.