考虑张拉-剪切复合破坏的离散元强度折减法在边坡稳定性分析中的应用

Application of strength reduction method considering tension and shear failures for slope stability analysis based on DEM

在离散单元法的理论基础上,将强度折减法用于边坡的稳定性评价中,从而克服了基于连续介质理论分析方法的不足。结合边坡的破坏模式,提出了考虑张拉-剪切复合破坏的离散元强度折减法,基于Fish语言,在颗粒流软件PFC3D中编写并实现了离散元强度折减法。通过对相应细观参数的折减,采用临界位移及特定平均不平衡力比率作为边坡失稳与否的判据,对边坡的稳定情况及破坏演化规律进行分析。结合水厂铁矿高陡边坡实例,得到边坡的安全系数为1.575,其破坏是微裂纹由坡脚向坡顶逐渐发展贯通所致。

To overcome the original limitations of the continuum analysis,a strength reduction method considering tension and shear failures was introduced from the viewpoint of discrete element method(DEM),and applied to rock slope stability analysis.In this regard,the critical displacement and ratio of average unbalanced mechanical force as the failure criteria to judge the unstable failure of slope,the micro-parameters such as bond tensile strength,bond cohesion strength and friction coefficient were reduced to analyze slope stability.By using the built-in language Fish provided by PFC3D,safety factor can be finally calculated automatically.By means of this method,not only qualitatively judge the failure of slope,but also reproduce the instability process of slope.The proposed approach was used to evaluate the rock slope stability in Shuichang iron mine.The results show that the safety factor is 1.575,and failure primarily generated at the bottom of slope,and gradually developed up towards.