The three-dimensional(3D) crack propagation is a hot issue in rock mechanics.To properly simulate 3D crack propagation,a modified maximum tangential tensile stress criterion is proposed.In this modified criterion,it is supposed that cracks propagate only at crack front in the principal normal plane.The tangential tensile stress at crack front in the principal normal plane in local coordinates is employed to determine crack propagation,which is calculated through coordinate transformation from global to local coordinates.New cracks will propagate when the maximum tangential tensile stress at crack front in the principal normal plane reaches the tensile strength of rock-like materials.Compared with the previous crack propagation criteria,the modified crack propagation criterion is helpful in calculating 3D crack stress intensity factor,and can overcome the limitations of propagation step determined by individual experiences in previous studies.Finally,the 3D crack propagation process is traced by element-free Galerkin method.The numerical results agree well with the experimental ones for a frozen resin sample with prefabricated 3D cracks.
Dunfu ZhangWeishen ZhuShucai LiBo ZhangWeidong Wang
利用非连续变形分析岩石断裂方法(Discontinue Deformation Analysis for Rock Failure,DDARF)数值模拟技术对平行节理岩体试件进行理论分析和数值模拟,研究了不同侧压力状态和原生裂隙角度等物理参数对剪切破坏和峰值强度的影响程度,指出侧压力和裂隙角度是岩体发生剪切破坏的主要原因。依据实际地下工程情形,建立具有平行节理岩体的地下洞室模型,并利用非连续变形分析方法(Discontinue Deformation Analysis,DDA)模拟地下洞室开挖过程围岩结构位移和稳定性分析,研究结果表明,平行节理岩体在不同地应力条件和裂隙角度下对洞室周围岩体稳定性具有不同程度的影响。
