3D SEISMIC RESPONSE OF LARGE ROAD TUNNEL WITH DIVERGENCE/CONFLUENCE PART

Abstract

 This study analyzes three-dimensional seismic response for a ramp tunnel of the Yamate Tunnel, which consists of divergence and confluence parts, using a detailed model. Quantitative evaluation is made for displacement, stress and section force, when the tunnel is subjected to a level 2 earthquake. The major findings are as follows: 1) seismic responses is three-dimensional, rather than two-dimensional as assumed for standard seismic design codes; 2)section forces change considerably at the connection of the rump tunnel with the main tunnel. Based on these findings, it is suggested that for a large-scale tunnel structure with complicated configuration, a three-dimensional analysis using a detailed model could be used for the purpose of seismic design.