Abstract:In view of the limitation of crack propagation in previous studies and the shortage of fracture mechanics theory, based on Abaqus platform, the numerical simulation of crack free propagation based on fracture mechanics is realized by using the method of confining channel integral and mesh resection. The results show that the SCB model is consistent with the theoretical results of the International Society of Rock Mechanics (ISRM). 。 when the yi value is 0, the specimen is subjected to pure type ii. for the scb model with s/r =0.8, type ii crack propagation mode appears only at a/r =0.7 and α=65°. the crack angle of the pure die ii decreases with the increase of the crack length ratio, but increases with the increase of the span height ratio (s/r); the crack growth process is numerically simulated, and the crack occurs from the crack tip and propagates towards the upper loading point. When the crack angle increases, the value of the crack starting angle increases and its value decreases with the increase of the span ratio (S/R). Moreover, the value of the crack starting angle increases first with the crack length ratio (a/R) Less. the crack initiation angle almost occurs when the crack length ratio (a/r) is 0.5.