某排土场边坡变形的二维颗粒流仿真研究

PFC^(2D) simulation for deformation of the waste-dump slope

排土场失稳破坏将产生重大的灾难性后果。由于排土场的特殊性,其失稳变形破坏机制更为复杂。以福建某露天矿排土场为原型,用颗粒流软件PFC2D对其进行饱和工况下的变形破坏过程模拟,根据坡形变化图、位移矢量图以及测量圈的孔隙率监测数据探究排土场的破坏机制,总结排土场变形破坏规律。结果表明,上部堆积体最先产生滑移,对下部产生堆挤,使得坡脚隆起、细颗粒挤出,最终导致整体性滑移;于基岩面附近产生沿基岩面的折线滑动,越靠近临空面则逐渐演化为圆弧滑动;变形过程中,孔隙率变化可分为两类:Ⅰ类孔隙率由大变小,Ⅱ类由小变大,两者在坡体破坏之时孔隙率增长速度接近。研究结果对排土场边坡的稳定分析具有理论和实际意义。

The failure of waste dump slope will cause results. Due to the particularity of waste-dump slope, its failure mechanism becomes more complex. Taking a waste-dump slope in Fujian as an object, we simulate the deformation and failure process of the slope by PFC-2D under saturated condition. The failure mechanism and law of the waste-dump slope have been concluded according to the slope shape variation, displacement vector graph as well as the monitoring data of porosity comes from measuring circle. The simulation results show that： the upper accumulated body slides firstly, then it squeezes the bottom part so that the slope toe bulges and fine particles are squeezed out, finally, the whole slope generate slip. Near the bedrock, the slope generate a fold line slide along the bedrock surface, but the sliding surface would gradually evolve into the arc-shaped when it is closer to the free surface. During the deformation, the change of porosity can be divided into two classes, Ⅰ is decreasing, Ⅱ is increasing, and they came to a approximate growth rate when the slope is destroyed. The results provide theoretical and practical reference to stability analysis of waste-dump slope.