Full-decay induced polarization multi-parameter tomography method for tunnel water inrush ahead prospecting: A case study

The geological structure, hydrology, and geomorphology of the Gaoligongshan tunnel are very complex due to its location in the zone where the Indian and Eurasian plates collide. Therefore, several water inrushes and jams were encountered during the construction process using TBMs. The application of geological prospecting can effectively reduce the occurrence of geological hazards. However, locating adverse structures relying on one geophysical parameter is prone to bias. In order to ensure the safety of tunnel construction while ensuring construction efficiency, a multi-parameter inversion imaging method based on full-decay induced polarization (IP) is proposed. Combined with geological analyses, the proposed method can image multiple geophysical parameters and determine the size, scale and area of water-bearing structures from a single test. With proposed method, the Gaoligongshan tunnel was passed through the detection section successfully. Herein, we present a case study that provides a valuable reference for the speed regulation of TBM construction under similar geological conditions.