Anomaly prediction ahead tunnel face using tunnel electrical resistivity prospecting system (TEPS) in Danyang

Abstract

Anomalies in tunnel ahead cause various problems, such as ground settlement, sinkholes and groundwater inflow during tunneling. Therefore, the accuracy of predictions of the location and size of anomalies is essential for safe tunnel excavation processes. TEPS, known as a tunnel-ahead prediction method, analyses electric fields through the tunnel-ahead rock mass between sensors attached to the tunnel face. TEPS requires approximately two hours overall for measurements and analyses, and it predicts 3-4 times the tunnel diameter ahead of the tunnel face. In this study, tunnel-ahead prediction tests are conducted using TEPS in a railway tunnel located in Danyang, South Korea. The tunnel passes through limestone regions, and hard rock region occasionally appears. The tunnel was excavated safely based on the predicted information.