Abstract
The evaluation of the detailed inspection of the tunnel linings of the various Nippon Expressway companies (NEXCO) is carried out, based on the Tunnel-Lining Crack Index (TCI). In order to increase the precision and efficiency of inspections of tunnel linings in expressways, this paper analyses the data from multiple detailed inspections of 9 683 spans in 99 tunnels, in an effort to incorporate the progressive propagation of cracks as an index of quantitative evaluation. As a result of this data analysis, it was found that it is possible to evaluate the progress of propagation quantitatively, using the TCI.
