ANALYTICAL AND EXPERIMENTAL STUDY OF WATER SEEPAGE PROPAGATION BEHAVIOR IN THE FAULT

Coal mine water inrush has an impartible relationship with the fracture zone such as faults, which deeply threaten the safety production in China. In order to study the water seepage behavior in the fault and the impermeability of the fault when water inrush through fault occurs, some water inrush cases through faults were analyzed, and water injection tests which drilled one injection borehole and one observation borehole into the fault zone were carried out at one coal mine. The breakdown pressure, reopening pressure, as well as the initial water seepage pressure, impermeability and the initial hydraulic conductivity of Puzizhier fault, were obtained from the result of the water injection tests. The study shows that water seepage in faults goes through three stages which consist of pore flow, fracture flow and pipe flow. It shows a process of the fine particulates and existing in-fill in the fault zone washing out and original and newborn cracks expanding and connecting. The results of water injection tests can be thought to show the fault healing effect under the underground pressure. In addition, the risk of water inrush through faults owes a great deal to the characteristic of water source.