Numerical Simulation on Mechanism of Pre-Splitting Crack under Filling-Mining

Based on the new mining method in GaoFeng mine, the mechanism of the pre-splitting crack to the explosive stress waves was simulated by using JWL state equation of high explosive under filling-mining. On the basis of the main indexes Peak Particle Vibration (PPV), using the explicit dynamical analysis software package (LS-DYNA), the laws of the propagation characteristics of explosion stress waves and the attenuation were analyzed into pre-splitting crack and the interface of different medium under filling-mining. The results showed that the PPV value appeared in sharply attenuation when explosion stress waves transfer pre-splitting crack, it means pre-splitting crack has a good damping effect, and damping ratio is up 80% to 90%. The weak structures exist in the interface of different medium, which has a certain damping effect between 3% to 10%. In the side near the explosion source, the pre-splitting crack and interface behaved a certain gathering effect, and the more the distant of the pre-splitting crack or interface was closer, the gathering effect was more remarkable, and the highest ratio could reach 25%.