Detection Technology of Groundwater Seepage Field Based on Seismic Electric Effect of Double Electric Layers

The safe disposal of nuclear waste is a pressing concern domestically and internationally. Over ten millennia, nuclear waste migrates through cracks in the rock mass of the disposal reservoir and enters the living area of human beings, causing certain harm to ecology, environment and living range. How to distinguish and monitor its migration path and the seepage field of groundwater migration medium is a research hotspot. At present, there are different kinds of hydrogeological test methods for monitoring the flow velocity of groundwater, and their application is relatively mature. There is a lack of technology to measure the flow direction of groundwater velocity in the preselection area of Beishan high discharge disposal reservoir in Gansu Province, which is characterized by hard, low permeability and closed rock mass. This study employed a three-dimensional sonar vector seepage field tester to detect Xinchang and Zhouzhou faults in Beishan, Gansu province. The findings revealed that the groundwater flow velocity in Xinchang F31 fault and five nearby 100m boreholes is 10-10m/s, and the main seepage direction is northwest to southeast. The flow velocity of the groundwater in the three 10m shallow holes in the Zhouzhoujing fault pit is 10-10m/s, and the main seepage direction is from northeast to southwest. Among them, the abnormal mutation of permeability velocity is consistent with the development of regional structural fracture. By verifying and comparing hydrogeological data from Beishan, it is found that: In the pre-selected area of the high-level waste disposal repository, the permeability coefficient of rock mass is about 10-10m/s, and the velocity of groundwater is 10-10m/s, which is consistent with the velocity of groundwater measured in this experiment. The accuracy of seepage velocity reaches 10-10m/s, and the direction error of flow field is 0~ 2°. The technique has high accuracy, scientific and feasibility, and provides theoretical and technical insights for solving the problem of groundwater seepage field detection in environmental geotechnical engineering such as preselection area of disposal reservoir, dam, and foundation pit and oil storage.