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通过对预制裂纹的大理石矩形板的剪切试验,分析了加载方式和预制裂纹的几何参量a/w对岩板产生Ⅱ型断裂模式的影响.当a/w<0.30时,岩板在2种加载方式下均能沿预制裂纹尖端连线发生Ⅱ型剪切断裂;当a/w>0.30时,岩板的断裂模式以Ⅰ型张拉裂纹为主.通过有限元计算所得岩板内部状态参量的分布规律,利用最小二乘法对计算所得的KⅡ因子进行多项式拟合,建立相应边界条件下几何修正函数,并通过试验计算断裂韧度KIIC.最后,利用辅助劈裂试验,验证了a/w对岩板Ⅱ型断裂的影响的实质是由于岩板的预制裂纹外部的岩石优先开始发生劈裂.
Through the shear tests on the precast rectangular marble plates, the influence of the loading mode and the geometric parameters a / w of the pre-crack on the type Ⅱ fracture mode of the rock slab is analyzed. When a / w <0.30, Type Ⅱ shear fracture can occur along pre-fabricated crack tip connection under loading mode. Type Ⅰ tensile fracture is the main mode of failure for a / w> 0.30. By means of finite element analysis, the internal state parameters , The least squares method was used to fit the calculated KII factor through polynomial fitting and the geometric correction function under the corresponding boundary conditions was established and the fracture toughness KIIC was calculated through experiments.At last, the auxiliary splitting test was used to verify the a / w The essence of the influence on the type Ⅱ fracture of the rock plate is that the rock outside the prefabricated rock of the rock plate preferentially starts to split.