岩石闭合裂缝的压剪断裂形态

COMPRESSION SHEAR FRACTURE FORM OF ROCK WITH CLOSE CRACK

介绍了对含闭合裂缝岩石试件在达到峰值压剪荷载时卸荷的裂缝断裂形态观察结果。结果表明，原有闭合裂缝已张开；裂缝尖端区域岩石晶粒已破碎，并可见碎粒剪切错动与偏转；次生裂缝组的走向与微裂区的形状呈不对称的桑叶状，与张开裂缝（切口）尖端岩石断裂形态相似；岩石压剪主剪断面沿该破裂区上部边界扩展。

The observational result of crack fracture form for rock samples with close crack under unloading after the peak compression shear load. The original close crack becomes open and rock grains of crack tip zone are broken. The shear shift and deflection of broken particle can be seen. The induced cracks are of the shape of asymmetrial mulberry leaf, which is similar to the fracture form of open crack (notch ) tip. The principal shear fracture plane of rock under compression shear state is to propagate along the upper boundary of the fracture zone.