Vector resistivity monitoring technology assembled on a TBM

The traditional geophysical advanced detection methods, which necessitate the placement of transmitting and receiving devices on the tunnel face and the sidewall, encounters significant limitations when confronted with the challenges of water and mud inrush disasters in tunnel boring machine (TBM) tunnels. Given the constraints of efficiency and limited construction space, a vector resistivity monitoring technology is proposed, which involves arranging the current electrodes on the surface and measuring electrodes on TBM. Based on finite element method with unstructured tetrahedral grids, a three-dimensional geophysical model including the tunnel is constructed and forward modelling of low resistivity anomalous bodies with different shapes and positions is carried out. The apparent resistivity in different directions is calculated, and the distance between the anomalous body and TBM is inferred according to the low value anomaly of the vector resistivity curve of both sides. The spatial position of the anomalous body is inferred according to the shape and relative relationship of the vector resistivity curves near the low value anomaly. Finally, the position of the sphere low resistivity anomalous body is predicted through the gated recurrent unit. These results preliminarily verify the feasibility of the vector resistivity monitoring technique assembled on a TBM.