法向压缩载荷对II型裂纹扩展的影响规律研究

压剪共同作用下裂纹是地下岩体中广泛存在的，为了研究法向压缩载荷对剪切型即II型裂纹扩展的影响规律，利用砂岩制作了单边裂纹试件，通过岩石剪切实验系统对不同法向压缩载荷作用下的裂纹进行了剪切实验研究，结果表明法向压缩载荷对裂纹的起裂及扩展起到抑制作用，随着裂纹法线压缩载荷的增大，裂纹起裂角逐渐减小；同时，得出法向压缩载荷与II型裂纹极限应力强度因子之间的关系，随着法向压缩载荷增大，岩石II型裂纹极限应力强度因子也随之增大。运用ABAQUS模拟软件，对不同压缩载荷作用下压剪裂纹的扩展进行模拟研究，得出了裂纹尖端II型应力强度因子随压缩载荷的变化规律。

The study of influence law about mode II crack propagation

In order to study the impact of the normal compression on shear (mode II) crack propagation, Sandstone is used to make the unilateral crack specimen. Shear experiment on cracks which are under different normal compression loads was carried out by rock deformation test system. The results show that the normal compression loads play an inhibitory effect on the crack initiation and expansion. With the increase of the normal compression loads, initial crack angle decreases. While, the relationship between the normal compression loads and mode II crack critical stress intensity factor is achieved. The rock mode II crack limit stress intensity factor also increases with the increasing normal compression loads. Compression-shear crack propagation was simulated under different compression loads by using ABAQUS. Meanwhile, Variation law of mode II stress intensity factor in crack tip was obtained with variation of compression loads.