CALCULATOIN OF STRESS INTENSITY FACTOR OF UNSTABLE ROCK

Perilous rock collapse is one of the main types of geological disasters in mountain areas. The root cause leading to perilous rock instability is the crack growth of main control structural surface. Using the theory of linear elastic fracture mechanics analysis methods, the approximate analytical formula to calculate stress intensity factor(SIF) of perilous rock under gravity is established by introducing the stress concentration coefficient method. The SIF can be used for unstable rock control structure surface and cracks collinear. Based on ABAQUS J-integral and Displacement extrapolation method, the progress of perilous rock crack tip stress intensity factor is derived. Instance computational analysis shows that the two numerical results are close to the approximate analytical results, which can verify the reasonableness of calculating perilous rock SIF by ABAQUS.Finally, simulation is given for the impact on stress intensity factor by crack angle and the width of the free surface change. Using ABAQUS to analysis unstable rock, and drawing the trend graph of the stress intensity factor under the influence of various factors can be used to speculate that the instability of the critical condition of the unstable rock.