含倾斜边裂纹岩石冲击断裂模拟试验

为模拟岩石在冲击荷载下，裂纹与加载方向不同角度情况下的断裂行为，利用透射式焦散线测试系统，采用单边切口三点弯曲梁试件，进行三点弯曲梁冲击断裂试验。研究结果表明：含倾斜边裂纹试件受到正应力和剪切力作用，裂纹为复合型裂纹，裂尖产生的焦散斑为复合型焦散斑；预制裂纹与加载方向的夹角变化时，动态应力强度因子、裂纹扩展时间以及裂纹扩展速度都随之变化；预制裂纹与加载方向的夹角增大时，裂纹扩展速度的最大值增大，裂纹扩展速度的振荡性增强；当荷载的加载方向与预制裂纹的方向一致时，裂纹起裂最快，裂纹为I型裂纹。冲击载荷方向与预制裂纹夹角增大时，扩展裂纹表现为复合型特征，动态应力强度因子KdⅡ表现越明显，其最大值随夹角的增大而增大。

Simulation experiment of rock fracture containing inclined edge crack under impact load

In order to simulate fracture behavior of rock under different angles between pre crack and loading direction,the fracture experiments of the three point bend beam containing unilateral incision subjected to impact load were carried out by transmission type caustics test system.Experimental results show that inclined edge crack specimen is subjected to normal stress and shear stress.The growth cracks are mixed code cracks and the focal speckles at the tips of crack are also mixed.The dynamic stress intensity factor,crack propagation time and the crack propagation velocity are associated with the angle changes between pre crack and the loading direction.As the angles between pre crack and the loading direction increase,the maximum of crack propagation speed increases,and the oscillation of the crack propagation velocity also increases.When the loading direction is the same as the pre crack direction,the crack initiates the fastest,and the crack is the Ⅰ type crack.As the angles between loading direction and pre crack direction increase,the crack takes on mixed characteristic,the dynamic stress intensity factor KdⅡ represents more obviously and its value increases.