Adaptive finite element forward of MT field in a 2D structure with near-surface transversal conductivity variation

Abstract The Qiandao Lake water diversion project can greatly improve the water use problem of Hangzhou citizens. The site selection of the underground passage has been investigated by MT sounding method in this project. In this paper, the type of suspected anomaly filling (air, mineral water, sediment) found under cement bridge is studied by using the adaptive finite element algorithm with continuous change of conductivity. The results show that this method can identify the type of filling material in underground caves well, and can roughly understand the volume proportion of water in caves.