Evaluation of Electrical Resistivity for Non-destructive Seepage Detection on an Urban Underground Diaphragm Wall

With the continuous development of urban underground space, non-destructive methods for diaphragm wall leakage detection are becoming increasingly important. Recent studies have shown that the apparent resistivity, stimulated current, and self-potential can be used as indicator parameters for non-destructive diaphragm wall leak detection. The diaphragm wall seepage evaluation of a subway station was carried out using the above indicator parameters. The response characteristics of apparent resistivity, stimulated current, and self-potential were obtained before and after excavating the diaphragm wall. The results obtained by this study reveal that an area is very likely to be a seepage area when there are significant differences amongst the three measurement parameters. The self-potential is greatly affected by field interference; the stimulated current is a direct sign of seepage, and indicates that seepage occurs when the stimulated current increases; the apparent resistivity macroscopically indicates rupture or seepage in the diaphragm wall. The field experiment verified the feasibility of detecting diaphragm wall seepage using coupled analysis based on electrical resistivity and self-potential methods.