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岩石在压缩加载过程中的变形由岩石母体的线弹性应变和微裂纹引起的非弹性应变组成,微裂纹扩展与裂纹尖端应力强度因子大小有着密切的关系.基于细观力学方法,分析了岩石微裂纹相对滑动的条件及扩展准则.运用RFPA2D程序,对在压缩条件下岩石单一微裂纹的扩展过程进行了数值模拟,结果表明,微裂纹在起裂扩展前,在相当一段时间内,原生裂纹上下2个裂纹面会发生相对摩擦滑动;岩石受压时微裂纹产生沿最大主压应力方向扩展的次拉伸裂纹,该次拉伸裂纹是岩石产生劈裂破坏的主要因素.
The deformation of rock during compressive loading is composed of the linear elastic strain of rock matrix and the inelastic strain caused by microcracks. The microcrack propagation is closely related to the size of stress intensity factor at crack tip. Based on the meso-mechanics method, The relative sliding conditions of crack and the propagation criterion are studied.The numerical simulation of the propagation of single microcracks under compressive conditions is carried out by using RFPA2D program.The results show that before microcracks propagate, The two cracked surfaces will be relatively frictional sliding. When the rock is compressed, the micro-cracks produce secondary tensile cracks along the direction of the maximum principal compressive stress. The secondary tensile cracks are the main factors for the splitting failure of the rock.