ABSTRACT
Deformation causes of tunnel lining include external causes in which forces are applied from outside the tunnel (hereinafter referred to as “external force”) and internal causes due to the material, construction etc. However, there are many unclear aspects in the characteristics of cracks classified according to their causes. Thus in this research, we set thresholds related to the possibility of deformation caused by external force from the cracks development plans of the linings in the road tunnels managed by Nippon Expressway Company (hereinafter referred to as “NEXCO”) of Western, Central and Eastern Japan using Tunnel-Lining Crack Index (hereinafter referred to as “TCI”). Moreover, we analyzed the relationship between the set thresholds and the tunnels where external force deformations were observed.
