Harmony Search-Based Optimization System for Electrical Resistivity Surveys to Predict Cavities Ahead of a Tunnel

Accurate prediction of cavities ahead of a tunnel face is essential for ensuring stable and efficient construction. In this study, a harmony search-based optimization system was developed to estimate cavity characteristics ahead of a tunnel face, such as the distance between the cavity and tunnel face, the radius of cavity, and the electrical resistivity of cavity. The relationship between the cavity characteristics and electrical resistivity was derived to apply as the objective function of inverse analysis. The inverse analysis was conducted using the derived analytical solution corresponding to the electrical resistivity values of the ground formations containing a cavity. A series of laboratory experiments were performed to validate the developed system, and the results showed that the system could accurately estimate the cavity characteristics. In conclusion, the developed system can be a powerful tool for minimizing potential risks by predicting cavity characteristics ahead of a tunnel face.