Determining the Seepage Stability of Fractured Coal Rock in the Karst Collapse Pillar

摘要: The karst collapse pillar (KCP) is a common geological structure in the coal mines of northern China. KCPs contain many fractured rocks, which can easily migrate under action high-pressure water. destruction or instability cementation between rocks directly induce coalmine water-inrush accidents. To study seepage stability cemented and rock triaxial pressures, self-designed testing system was used permeability k non-Darcy factor β were tested. Furthermore, 1D equations to calculate evolution criteria loss stability. results show following: (1) KCP pressures be destroyed. damaged body mainly exists bulk form, depends on effective stress particles. (2) process combination pore flow, fracture pipe transition state closely related change magnitude β. (3) Under long-term effect confined underground water, migration small particles will increase structural porosity. If parameter reaches threshold value, evolve into pipeline flow state, eventually causing accident.