采用“裂纹线应力场”分析方法,推导双轴压缩下有限岩板内闭合裂纹尖端应力强度因子的近似解析解,分析裂纹表面摩擦因数、侧压系数对裂尖应力强度因子的影响;运用有限元法对同一问题进行数值研究,并与解析解进行比较。研究结果表明:在岩体工程要求的精度之内,采用“裂纹线应力场”分析方法与有限元法这2种方法得出的结果基本吻合;裂纹长度α与岩板宽度形之比对裂纹尖端的应力强度因子有影响,按无限岩板情况计算裂纹尖端应力强度因子,其适用范围应有一定上限,即α/W≤0.2;当α/W〉0.2时,应当考虑实际岩板的自由边界条件对裂纹尖端场的影响。
Model of closed-crack in finite-rock-plate under biaxial compression was established. Based on crack-line analysis method, the approximately solutions for the crack tip stress intensity factor(SIF) were deducted. The influences of friction coefficient and side pressure coefficient on crack tip stress intensity factor were analyzed. Using the finite element method, the numerical study was given to the same question. The results calculated by two methods are similar within the accuracy requirement in engineering. The ratio of crack length a and plate width W influence SIF. There exists an upper limit, i.e., α/W≤0.2. When α/W〉0.2 for the application of infinite-plate formula to calculate SIF, the rock-plate should be considered as finite-rock-plate and the influence of boundary conditions on crack tip should not be neglected.