单轴压缩下含倾斜单裂纹砂岩试件裂纹扩展量测研究

A study of crack propagation measurement on sandstone with a single inclined flaw under uniaxial compression

选用砂岩作为试验材料,进行不同倾斜角度单预制裂纹的单轴压缩试验研究,透过裂纹扩展量测技术以及配合相关断裂准则,得到:(1)理论与实验的裂纹起裂角随裂纹倾斜角增加而增大;(2)透过相关断裂准则,砂岩试件在裂纹尖端产生反翼裂纹是因为剪力破坏;(3)在单轴压缩作用下砂岩试件裂纹扩展受单裂纹的倾斜角影响,当裂纹倾斜角较小时,裂纹不易起裂;当裂纹倾斜角较大时,裂纹起裂比较容易;(4)在单轴压缩作用下砂岩试件则受单预制裂纹的倾斜角影响,当裂纹倾斜角较小时,裂纹扩展属于非稳定扩展;当裂纹倾斜角较大时,裂纹扩展属于稳定扩展;(5)在单轴压缩作用下砂岩试件裂纹尖端A侧与裂纹尖端B侧的裂纹扩展平均速度随裂纹倾斜角增加而降低。

Uniaxial compression test was conducted on sandstone with a single pre-existing flaw at various inclined angles.Employing crack propagation measuring techniques and relevant fracture criteria,some conclusions are drawn as follows.（1） The crack initiation angles of the sandstone specimen obtained from both theory and experiments increased with increasing flaw inclined angle.（2） Using a fracture criterion,the appearance of a anti-wing cracks at the tip of the crack of the sandstone specimen was attributed to shear failure.（3） Under uniaxial compression,crack propagation in the sandstone specimen is influenced by the single flaw inclined angle;a small flaw inclined angle it is not easy to crack initiation,while the large flaw inclined angle,allowed easy crack initiation（4） Under uniaxial compression,crack propagation in the sandstone specimen,which was influenced by a single pre-existing flaw,was unstable when the flaw inclined angle was small;and stable when the angle was large.（5） For the sandstone specimen,the average crack propagation velocity for A and B sides of the crack tip decreases with increasing flaw inclined angle.