Mechanical mechanisms of fault self-locking and activation and its stability control

In view of the hard issue of whether or not the fault activation will occur when the fault is affected by mining activities, the fault band, hanging and footing walls together are treated as a system and its stability is studied through theoretical analysis. The results have shown that there are two stress ratio state parameters in the system, both of which are the function of system parameters such as cohesive force of fault surface, internal friction angle, fracture fluid pressure and vertical stress. The system stability is determined by the relationship between the stress ratio and the stress ratio state parameters. The closer the fault dip angle is to the shear slip characteristic angle, the smaller the cohesive force of fault surface and internal friction angle, the greater the pressure of fracture fluid, and the more prone to leading to unstable state of the system. The influence of vertical stress on the system stability varies with different magnitude relationships among cohesive force, fracture fluid pressure and internal friction angle. The stability of system can be effectively controlled by the measures of adopting pre-grouting, drilling hole to drainage fracture fluid and adjusting the construction scheme to change the stress ratio The results have reference significance to the exploitation of underground resources in the areas with faults, the underground engineering construction and the prevention and reduction of earthquake disaster in these areas. © 2019, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.