基于微观裂隙扩张的采场底板突水机理研究

基于矿山压力和岩层控制理论,分析了工作面附近支承压力及底板水压的空间分布特征,确定了两者对底板的力学作用机制。通过建立裂隙力学模型,从微观角度研究了支承压力和水压对裂隙的作用效果;以薄板理论为依据,从宏观角度研究了含水层水压对底板有效隔水层的作用机理,并给出底板突水极限水压值的计算公式。结果表明:支承压力的增大会导致裂隙渗透系数的减小;水压的增大会导致岩体强度的降低和裂隙劈裂长度的增加。采场底板突水的实质是采动引起的矿山压力和承压水水压共同作用下微观裂隙的扩张和底板有效隔水层的断裂。

Mechanism study of floor water inrush around mining field based on micro-crack extension

Based on the mine ground pressure and strata control theory, spatial distribution characteris-tics of ground pressure and floor water pressure around mining field have been analyzed in this paper, and then the mechanical effects of both these pressures on the coal floor have been determined. By set-ting up mechanics model, the effects of ground pressure and water pressure on a set of tilted cracks have been studied from a microcosmic point of view. Based on the thin plate theory, the effects of water pressure on the effective water-resisting layer have also been studied from a macroscopic point of view. Finally, a theoretical formulae of limiting hydraulic pressure has been deduced. The results have shown that the increase of abutment pressure can lead to the decrease of permeability coefficient; the increase of water pressure can cause the attenuation of rock mass strength and the increase of fissure length. The essence of water inrush in mining field is the result of propagation of micro-cracks and fracture damage of the effective water-resisting layer caused by ground pressure and water pressure.