Abstract: Fault is an important factor to influence ground subsidence above goaf. To solve this problem, a 3-D geological model of the goaf has been built by using the numerical method. To contrast the existence of the fault, the rule of the goaf surface subsidence has been discussed. The settlement which are affected by the dip angle of a fault, its relative position with the mined-out zone, and its mechanical properties are analyzed in detail. The research shows that the fault enlarges the settlement values, and discontinues the surface deformation. The existence of the fault makes the settlement basin center deviate to the fault side. When the dip angle of a fault is between 40 to 50 degrees, the maximum volume of the surface subsidence appeared. When the dip angle is between 35 to 40 degrees, the maximum volume of the goaf roof subsidence appeared. The decline of the shear strength of fault accelerates the settlement value, and as it approaches or exceeds the soil friction angle, this relation is weakened.

Key words: goaf, settlement law, fault, numerical simulation, subsidence