Research on mechanical properties of coal and its application

The deformation failure mechanism of coal and the effect of initial cracks and closure on coal strength. The research results show that the process of coal failure can be divided into five stages, including damage degradation, quasi-linearity, damage steady evolution, damage accelerating evolution and post-peak softening. With closure of massive initial fractures and void structures in the Shenfu's coal, the strength and the elastic modulus of coal will be improved significantly. So, it's more reasonable to simulate the excavation process by using elastic modulus which has been improved. Acoording to the numerical simulation results, the reasonale thickness of supporting is chosen as 20-25 cm.