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为评价陕北神南矿区浅埋煤层开采对地下水及地表水的影响,对煤层上覆关键隔水土层的采动隔水性进行研究.在进行了神南矿区野外地质调查的基础上,采用中压三轴伺服仪测定神南矿区离石组黄土及保德组红土在三轴加载及卸载过程中的渗透系数,并结合采前、采后现场压水试验成果研究了浅埋煤层开采前后关键隔水黏土层渗透系数变化特征.试验结果表明:浅埋煤层开采引起薄层基岩整体切落,在贯通裂隙发育区上覆隔水土层失稳表现为渗透系数几个数量级的巨大增加;而在拉张区黏土层上部的离石黄土受地面裂缝影响渗透性变大;拉张区黏土层下部的保德红土处于整体下沉带,附加应力使其产生塑性变形,渗透性变小.这为判断砂土层中潜水水位下降幅度即浅埋煤层保水开采可行性提供了依据.
In order to evaluate the influence of shallow coal seam mining on the groundwater and surface water in the Shennan mining area of northern Shaanxi Province and study on the mining water-barrier property of the key aquifer overlying the coal seam.Based on the field geological survey in the Shennan mining area, Axis servo system to determine the permeability coefficient of loess in Linshi Formation and that of Baode Group in three-axis during the process of loading and unloading in the Shennan mining area. Combined with the results of on-site water pressure test before and after mining, The results show that the mining of shallow coal seam causes the whole bed of bedrock to be cut off completely, and the instability of overlying soil and water bed in the development zone of through crack is the huge increase of permeability coefficient of several orders of magnitude. The permeability of the limestone in the upper part of the clay zone is affected by the ground cracks, and the lower part of the clay in the tension zone is in the overall sink zone with additional stress to make the plastic deformation and permeability lower. Groundwater level in the subduction of shallow water that the feasibility of providing water-cut mining provides the basis.