Geophysical exploration of a long deep tunnel on the west route of South-to-North Water Diversion Project
南水北调西线千米深长隧洞围岩构造地球物理勘探

It is very important to explore for the weak geologic bodies and structures that may affect the tunnel safeness. We carried out geophysical and engineering geological exploration and integral interpretation to detect the geological structure, rock properties and water bearing characteristics in 2004 for the 20 km long deep tunnel between Make River and Jiaqu River on the west route of South-to-North Water Diversion Project. The paper presents the advantages of CSAMT tunnel exploration, data collection procedure and the data processing techniques for rough topography and complex media. According to the geophysical and engineering geological exploration results, the paper explains the geological structure characteristics of the 20 km tunnel media and indicates the faults, fractures and some anomalies that may cause danger for the tunnel construction.