Abstract:According to the stress characteristics of coal floor with faults,corresponding simplified mechanical model is built to obtain the equations of shear stress and normal stress on the fault,as well as the influential rules of fault dip on shear stress,normal stress and fault activation. At the same time,under the circumstances of different normal fault dips,the fracture distributions and seepage distribution of coal floor as well as the variation characteristics of inflow quantity of coal floor in the mined area are simulated with mining carried out by using the RFPA2D-Flow software. The numerical simulation reveals the formation principle of water inrush channel in coal floor with fault structure as well as influential rule of fault dip on water inrush in coal floor. Overall,the results indicate that normal faults with low dip angles are more easily activated to induce water inrush in coal floor,which has an important value in the case of coal floor with faults when waterproof coal pillars are needed.