2004 Volume 14 Pages 115-122
As a number of mountain tunnels without reinforcing bars are deformed and cracked by earth pressure, assessment methods of their strength have been researched and established to design countermeasures. On the other hand, there has been no well-established evaluation methods for the structural strength of urban tunnels with reinforcing bars, which are safer against earth pressure. Then, model tests and numerical calculation concerning the tunnels are carried out to investigate the mechanical properties of them. It is confirmed that the tunnels become stable by distributing stress in case of stiffness reduction and their strength can be grasped by using the numerical calculation described in this paper.