Mechanism And Numerical Simulation Of Rock's Crack Propagation Under Detonation Gas

The damage and fracture process of rock blasting is a complicated process. Owing to rock material's heterogeneity and anisotropism, in the abstract it is quite difficult to describe its composing characteristic well and truly; Because of the complex interaction between microdefects and macroscopic cracks under external load, the existing analytic method still can't research into this problem effectively; And that due to the limitation of experiment facilities and testing measures, it is unable to test the full field's meso-hiberarchy change, especially the heterogeneity stress and strain field accurately. Therefore, it is one of most important tasks to try our best to comprehend the mechanism of blasting damage and fracture of rock, to simulate the complexity characteristics and the full process of blasting occurrence and crack propagation of rock.On the basis of rock fracture mechanics and damage mechanics, the damage and fracture mechanism of rock is researched under the blasting stress waves and detonation gas'quasi-static load. The effect of detonation gas'quasi-static load on crack propagation is analyzed in depth. It is learned that crack propagation and rock rupture are both resulted from the detonation gas, which is the main cause to make crack extend in blasting engineering. And based on analysis above, the crack propagation process under detonation gas'quasi-static load is simulated with the numerical method.Based on cognition of rock meso-hiberarchy, the characteristic of rock material is described through some statistical laws (according to one certain weibull distribution or normal distribution) to consider rock heterogeneity. From meso-hiberarchy, a heterogeneity model is created to analyze rock fracture process and the effect of heterogeneity and initial geostatic stress on crack propagation. From the results, it is learned that homogeneity indices is a parameter to represent rock meso difference and a intrinsic factor to determine macro mechanics properties of different rock. If the initial geostatic stress is known, the angle between initial crack and maximum horizontal geostatic stress is smaller, the length of crack propagation is longer, and vice versa; The total propagation length is also becoming smaller with the initial geostatic stress increasing. Therefore, on condition of high initial geostatic stress and even the same geological conditions, the quantities of dynamite need increase to blast the rock .