(1.CCCC Tunnel Engineering Co., Ltd., Beijing 100102, China;2.Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China)
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.
柴栋,方广涛,邱春雄,等.多含水层渗流系统电导示踪模型[J].水利水电科技进展,2023,43(2):70-75.(CHAI Dong, FANG Guangtao, QIU Chunxiong, et al. Electric conductivity tracer model of a multi-aquifer seepage system[J]. Advances in Science and Technology of Water Resources,2023,43(2):70-75.(in Chinese))Copy