摘要
首先建立双向压缩条件下形成单一闭合裂纹的力学模型,考虑摩擦力的影响,计算出裂纹面的正应力和剪应力。分别运用有效剪应力准则和最大周向应力准则计算裂纹的初始断裂角。运用有效剪应力准则得出的初始断裂角只与岩石的抗拉强度和抗压强度之比有关。运用最大周向应力准则得出的初始断裂角受裂纹和荷载方向的夹角、裂纹面之间的摩擦系数、侧压力系数的影响。将两种理论分析的结果与实验结果进行对比分析得出:考虑摩擦力的最大周向应力准则更接近裂纹扩展的实际情况,建议工程中更多的采用该准则,而有效剪应力准则与实验结果不相符,有待完善。岩石闭合裂纹的扩展及断裂是一个复杂的过程,有待深入分析研究。
A mechanical model is built firstly for single closed microcrack under biaxial compression loading,and taking into account the impact of friction,the crack surface normal stress and shear stress are calculated.The effectual shear stress criterion to the maximum circumferential stress is used to calculate the initial fracture angle of microcrack.The effectual shear stress criterion shows that the initial fracture angle of microcrack is only related to the ratio of tensile strength to compressive strength of rock.The use of maximum circumferential stress criteria for closed microcrack shows that the initial fracture angle of microcrack is related to the angle of microcrack and loading orientation,coefficient of friction between the crack surfaces and the lateral pressure coefficient.The two theoretical analysis results were compared with the experimental results;it shows that the maximum circumferential stress criterion considering friction is closer to the actual situation of the expansion process of microcrack,it should be used more in engineering.The effect of shear stress criterion does not accord with the experimental results,which should be improved.The rock crack extension and fracture closure is a complicated process,and needs further study.
出处
《地下空间与工程学报》
CSCD
北大核心
2010年第5期969-974,共6页
Chinese Journal of Underground Space and Engineering
关键词
岩石
闭合裂纹
有效剪应力准则
最大周向应力准则
断裂角
rock
closed microcrack
effectual shear stress criterion
maximum circumferential stress criterion
fracture angle
