| In Japan, road tunnels are commonly constructed using conventional tunneling methods, and cast-in-place, unreinforced concrete is used for permanent linings. Recently, the use of precast permanent linings has been potentially considered to save manpower. In our latest studies, full-scale loading tests were conducted on precast permanent linings. These tests revealed that the spalling of the cover concrete, pushed out by the rebar around the joint, was a factor in determining the load-bearing capacity of the permanent lining. In this study, we develop a method for evaluating the cover concrete spalling in permanent linings. Furthermore, to verify the validity of this evaluation method, we conduct a numerical analysis to replicate full-scale load tests. The results of this study indicate that this failure mechanism could be reproduced by verifying the failure using the M-N failure envelope of the cover concrete section. |
