以宁夏灵新煤矿地下水库建设为工程背景，分析了在煤矿地下水库建设和运行过程中，可能对邻近含水层造成影响的两大因素:① 煤层工作面重复开采引起的覆岩裂隙导通含水层，会对矿区地下水资源造成初次影响;② 在高盐矿井水注入地下水库的过程中，由于浓度梯度的作用，矿物离子将主要沿着裂隙通道进行扩散，进而可能对矿区地下水资源造成二次影响。这2种影响方式都与采空区覆岩中的采动裂隙是否形成贯通的渗流通道密切相关。基于上述分析，首先通过固-液耦合相似模型试验与数值计算相结合的方法，分析了灵新煤矿拟建煤矿地下水库区域重复开采条件下采空区覆岩的裂隙网络演化规律和渗流通道特征，进而深入分析了重复开采对煤层上方各含水层的影响，具体表现在:一采区工作面回采结束后，采空区上覆岩层裂隙相互连通并扩展至K4含水层，但K3含水层与采空区之间未出现明显的渗流路劲，表明重复开采对K3含水层的影响较小。综合上述相似模拟试验和数值计算得到的裂隙网络特征，采用OpenGeoSys多场耦合数值模拟软件，模拟了高盐矿井水在采动裂隙网络中的渗流过程，分析了高盐矿井水在煤矿地下水库中封存后对上覆含水层的污染风险。研究结果表明:注水条件下，高浓度盐水首先在裂隙采空区流动，随后沿着覆岩断裂裂隙进入K4含水层，并最终在K4含水层及其邻近覆岩断裂裂隙中流动，渗流场离K3含水层较远。浓度场在自身重力所用下10 a后扩散速度有所减缓，在50 a内，浓度场主要在K4含水层邻近覆岩、K4含水层和底部泥岩中扩散，只有微量高盐矿井水会扩散至K3含水层中。

Taking the underground reservoir of Lingxin coal mine as the engineering background,the two factors affecting the adjacent aquifer were analyzed during the construction and operation of underground reservoir in the coal mine.First,the overburden fracture caused by the repeated mining will lead to the aquifer,which will have the first impact on the groundwater resources in the mining area.Second,in the process of high salt mine water injected into the underground reservoir,due to the effect of concentration gradient,the mineral ions will mainly diffuse along the fracture channel,which may have a secondary impact on the underground water resources in the mining area.These two factors are closely related to whether the mining fracture forms a through seepage channel.Based on the above analysis the evolution law of the fracture network and the characteristics of the seepage channel of overburden rock under the condition of repeated mining were analyzed through the solid liquid coupling similarity model test,and based on the discrete element method,the distribution characteristics of fracture network and the influence of repeated mining on the upper protected aquifer were further analyzed.The results show that the fractures in overlying strata in the goaf are interconnected and extend to the K4 aquifer under repeated mining and have little influence on the K3 aquifer after the completion of mining in No.1 mining area.Combining the characteristics of fracture network obtained by similarity simulation and numerical calculation,the seepage and diffusion processes of highly mineralized mine water in mining induced fracture network were simulated by using the Open GeoSys multi-field coupling numerical simulation software,and the pollution risk of mine water to the upper protected aquifer in the sealed reservoir after mass separation was analyzed.The results show that under the condition of water injection,only a small amount of mine water will be diffused into the K3 aquifer within 50 years when the highly mineralized mine water fills the gap space between the goaf and the K4 and K3 aquifers.

1 地质概况

2 重复开采覆岩裂隙与渗流通道演化规律

   2.1 固液耦合相似模拟试验

   2.2 相似模拟试验结果分析

   2.3 采动裂隙数值模拟

3 地下水库注水渗流场分析

   3.1 渗流-扩散数值模型的建立

   3.2 采动裂隙渗流数值模拟过程

   3.3 注水条件下裂隙渗流规律

   3.4 注水后浓度场演化规律

4 结论