危岩应力强度因子的计算研究

摘要

危岩崩塌是山区主要地质灾害之一,其主控结构面的断裂失稳是导致危岩崩塌的根本原因.运用线弹性断裂力学的理论,引入应力集中系数法,建立了自重作用下的危岩应力强度因子的计算公式,可用于主控结构面与裂缝共线的危岩稳定性计算.同时还推导了基于ABAQUS的J积分、位移外推法计算危岩应力强度因子的过程.通过实例表明,2种数值计算方法与解析结果十分接近,验证了ABAQUS计算危岩应力强度因子的合理性,最后模拟了危岩裂缝角度以及临空面宽度变化对危岩应力强度因子的影响.利用ABAQUS对危岩进行分析,并绘制应力强度因子在各因素影响下的趋势图,可以推测危岩失稳的临界条件.%Perilous rock collapse is one of the main types of geological disasters in mountain areas. The root cause leading to perilous rock instability is the crack growth of main control structural surface. Using the theory of linear elastic fracture mechanics analysis methods, the approximate analytical formula to calculate stress intensity factor (SIF) of perilous rock under gravity is established by introducing the stress concentration coefficient method. The SIF can be used for unstable rock control structure surface and cracks collinear. Based on ABAQUS J-integral and Displacement extrapolation method, the progress of perilous rock crack tip stress intensity factor is derived. Instance computational analysis shows that the two numerical results are close to the approximate analytical results, which can verify the reasonableness of calculating perilous rock SIF by ABAQUS. Finally, simulation is given for the impact on stress intensity factor by crack angle and the width of the free surface change. Using ABAQUS to a-nalysis unstable rock, and drawing the trend graph of the stress intensity factor under the influence of various factors can be used to speculate that the instability of the critical condition of the unstable rock.