含水层富水性与其危险性关系的力学分析

Mechanical analysis of relations between water abundance and fatalness of water inrush from underlying aquifers

煤矿生产实践表明,工作面底板含水层富水性强弱与其突水可能性存在着密切联系。通过对地下水与其上覆岩层作用力关系的分析,得到了地下水静水压力对上覆岩层有效压力的公式及裂隙中地下水流动形成的动水压力公式。2个公式表明煤层底板含水层富水性越强(即含水层空隙率n越大),地下水对工作面底板岩层的有效压力及动水压力也越强,使得底板岩层越易破坏,裂隙越易扩张、冲刷,造成突水危险性越高。根据以上结论可有针对性地进行煤层底板突水的防治工作,工程实践也证实了上述分析是正确的。

The coal mining practice shows that fatalness of water inrush is closely related with the wa- ter abundance in the underlying aquifers. In this paper, the effective stress of hydrostatic groundwater pressure on its overlying strata and the hydrodynamic pressure of groundwater in fractures have been obtained through the mechanical analysis of aquifers and its overlying strata. Two induced equations show that the bigger water abundance in underlying aquifers, the stronger effective stress of groundwa- ter on the floor strata and hydrodynamic pressure, which leads to more possible breakage in the floor strate, expansion and drainage of the cracks, and water inrush. Eventually, effective preventions of water inrush from coal seam floor strata are proposed and proven as feasible in engineering practice.