Karst cave prospecting using cross-hole ultra-high density resistivity method
SU Bao1(), LIU Xiao-Li2,3, WEI Xiao-Bo4, GAO Ge5, WANG Yun-Peng5
1. Guangdong Pearl River Delta Intercity Rail Transit Co., Ltd., Guangzhou 510335,China 2. School of Civil Engineering, Tsinghua University, Beijing 100084,China 3. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084,China 4. Guangzhou Metro Group Co. Ltd., Guangzhou 510330, China 5. Research Institute of Exploration and Development, Huabei Oilfield Company, PetroChina, Renqiu 062552,China
The prospecting of shallowly concealed karst caves is studied using the cross-hole ultra-high density resistivity method. The results are as follows. It was feasible to prospect Karst caves using existing survey boreholes according to the cross-hole ultra-high density resistivity method. The transverse and longitudinal distribution ranges of karst caves can be directed reflected by the distribution characteristics of the cross-hole resistivity obtained through forward and inverse calculations. Meanwhile, it was difficult to distinguish the connectivity between karst caves, and the depth deviation was the distance between two adjacent electrodes. It is suggested that the depth of the boreholes used should be consistent, the ratio of the borehole depth to the borehole space should be higher than 1.5, and the electrode space should be 1~2 m in practice.
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