侏罗纪煤田宝塔山砂岩含水层大流量大降深放水试验

为了在抽水试验的基础上进一步查明侏罗纪煤田宝塔山砂岩含水层的水文地质特征,开展了井下放水试验,单孔放水量平均值为237.91 m³/h,多孔放水量平均值为444.10 m³/h,宝塔山砂岩含水层地下水位下降最大值达310 m。通过大流量大降深放水试验,计算出含水层的渗透系数和单位涌水量,确定宝塔山砂岩含水层与白垩系、煤系间、三叠系含水层存在水力联系,探查了放水试验的影响范围及观测孔水位降深规律,论证了宝塔山砂岩含水层具有可疏性。基于宝塔山砂岩含水层水文地质特征,提出了下组煤开采底板砂岩水害防治方案。研究结果表明:井下大流量大降深放水试验可以最大程度激发含水层地下水位降深,有效弥补地面抽水试验的不足,在各含水层水力联系、疏放水影响范围和含水层可疏性评价方面得到的研究成果,可以作为矿井底板砂岩水害防治的依据。

Study on dewatering test with large flow and drawdown of Baotashan sandstone aquifer in Jurassic coalfield

In order to find out the hydrogeological characteristics of Baotashan sandstone aquifer in Jurassic coalfield on the basis of pumping test,underground dewatering test was used adopted.The everage water drainage value of single-borehole was 237.91 m^3/h,the average water drainage value of multi-borehole was 444.10 m^3/h,and the maximum ground water drawdown of Baotashan sandstone aquifer was 310 m.The permeability coefficient and unit water inflow of aquifer were calculated by means of the dewatering test with large flow and drawdown,it was confirmed that there were hydraulic connections between Baotashan sandstone aquifer and cretaceous,coal measures and triassic aquifer.The influence range of dewatering test and the drawdown law of observation borehole were investigated,it was proved that Baotashan sandstone aquifer can be drainaged.Based on the hydrogeological characteristics of Baotashan sandstone aquifer,the prevention and control scheme of floor sandstone water disaster from bottom sandstone with lower coal mining group was put forward.The results show that the dewatering test with large flow can stimulate the groundwater drawdown to the greatest degree,and effectively make up for the inadequacy of the surface pumping test.The research results of hydraulic connection among each aquifer,the influence scope of groundwater drainage and the drainage possibility of aquifer can be used as the basis for the prevention and control of sandstone water disaster in mine floor.