A study of estimation method for cause of tunnel lining deformation

Abstract: Deformation of tunnel lining is caused by such external factors as forces applied from outside (hereinafter referred to as “external forces”) and by such internal factors as forces applied by materials and constructions. But it is not clear in most of the cases that which factor causes what types (or features) of cracks. In this study, we extracted features of cracks that is typical to types from the crack deployment diagrams of road tunnel lining maintained and managed by East Nippon Expressway Company Limited, Central Nippon Expressway Company Limited, and West Nippon Expressway Company Limited (referred to as “NEXCO”, hereinafter). A crack index (hereinafter referred to as TCI: Tunnel-Lining Crack Index) was used to extract features from crack diagrams. This index allows us to quantitatively discern cracks caused by external factors from those cause by internal factors. We could also find the correlation between crack form and tunnel cross-section deformation of the tunnel whose lining was externally deformed by measuring the cross-section with a measurement vehicle system.