多含水层渗流系统电导示踪模型

在利用钻孔测定含水层水文地质参数时，如遇到多含水层情况，需使用栓塞系统对各含水层进行隔离探测，由于现场操作较为不便且钻孔条件要求高，故提出多含水层渗流系统电导示踪模型。在不使用栓塞系统的情况下，考虑含水层涌水或吸水等不同情况，通过测定抽水条件下各含水层的电导率，建立多含水层渗流系统电导示踪模型确定含水层渗透性参数。当钻孔中只存在涌水层时，直接利用电导率曲线面积与溶质质量的比例关系求解出流量；当钻孔中同时出现涌水层和吸水层时，根据溶质质量曲线的斜率可较准确地确定吸水层的位置，再由斜率的变化计算出含水层的流量。基于某工程实例采取3种方法求解各含水层的渗透系数、静水头、渗流速度、导水系数等水文地质参数，结果表明，采用电导示踪模型计算结果与同位素示踪测试及注水试验测试结果吻合较好，且电导示踪模型方法现场操作更为简便，可极大地提高含水层水文地质参数的测定效率。

Electric conductivity tracer model of a multi-aquifer seepage system

In hydrogeological survey, the situation of multiple aquifers is often encountered in borehole testing, and it is necessary to use packer system to isolate and detect each aquifer. Due to the inconvenience for field operation and high drilling conditions required, a multi-aquifer seepage tracing model without packer system was proposed. Considering different conditions of aquifer inflow and out flow without using plugging system, an electric conductivity tracer model for a multi-aquifer seepage system was established to determine the permeability parameters by measuring the conductivity of each aquifer during pumping. When only the outflow aquifer exists, the flow rate can be calculated directly by using the proportion relation between the area of conductivity curve and solute mass. When both outflow layer and inflow layer appear in borehole, the position of inflow layer can be found accurately according to the slope of electrical conductivity curve, and then the flow rate of aquifers can be calculated by the change of slope. In a field test, the hydrogeological parameters such as permeability coefficient, hydrostatic head, seepage velocity and water conductivity coefficient of each aquifer were calculated by using three methods. The results show that the detection results obtained by the conductivity tracing model is in good agreement with the isotope tracer test and water injection test, and the proposed model is simpler to operate, which can greatly improve the detection efficiency of aquifer hydrogeological parameters.