矿山压力下断层破碎带的导水性研究

Study on Transmissivity of Shattered Fault Zone Under Ground Pressure

为了探讨断层带充填破碎岩石条件下的导水性,实地采集岩样,配制了全砂岩、砂泥岩含量2∶1、砂泥岩含量1∶2等3组实验样品,模拟实际的矿山压力和渗流水压等条件,测量渗流速度,计算渗透系数。结果表明破碎岩石的泥质成分越高,则相同条件下的渗透系数越小;在相同的矿山压力条件下,破碎岩石的渗透系数与渗流水压呈非线性反比例关系。认为断层带破碎岩石中含粘土矿物较多时,岩石易吸水膨胀、软化,增加对地下水渗流的阻碍作用;瞬间施加的渗流水压使样品被压密,导致孔隙被压缩,表现为渗透系数减小;实验成果可用于近似判断断层破碎带的实际渗流特性,可合理解释某些矿区断层发育、承压水头高但却不导水的现象。

For studying transmissivity of fault zone filled with shattered rock,a simulation experiment was designed under the conditions of actual ground pressure and seepage force.Three sets of samples were collected in mine roadways,which were pure sandstone,sandstone mixed mudstone by 2∶1,and sandstone mixed mudstone by 1∶2.The permeability coefficient was calculated by measuring seepage velocity.The result shows that the higher composition of mud in shattered rock will result in the lower permeability coefficient under same conditions.The permeability coefficient of shattered rock presents non-linear inverse proportion with seepage force under the same underground pressure.It is concluded that the clay mineral contained in shattered rock of fault zone will result in the rock sopping up the water and being swelled and intenerated,which will block groundwater seepage.Otherwise,the seepage force,which was brought to bear on rock sample quickly,makes the holes in sample be compressed and decrease permeability coefficient.The result of the experiment can be used to estimate the actual seepage characteristic of fault zone filled with shattered rock approximatively.It can explain the phenomenon reasonably that some fault＇s transmissivity is very poor with high confined water head in some mines.