大理岩II型断裂规律试验及数值模拟分析

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.

Numerical and Experimental Analysis on Mode II Fracture Regular Pattern of the Marble

The in-plane mode II fracture of the Athenian marble slab with double parallel notches is studied in virtue of the finite element procedurecombined with rock tests. The analysis incorporates the influence of fracture behavior resulting from variation in both the position of the double notches and the cases of loading scheme. Based on the analysis of the numerical simulation, it is shown that the mode II fracture would take place when the ratio a/w is less than 0.3 in the two cases of loading scheme. After the geometrical correction factor is obtained from the results of the finite element method by the polynomial fitting method, the fracture toughness values, KIIC, determined for the specimens based on the ultimate load from the experiments and the geometrical correction factor. It is found that the value a/w is a critical parameter to determine the occurrence of the mode II fracture in the slab through the auxiliary splitting tensile tests.