Shaking table tests of transition tunnel connecting TBM and drill-and-blast tunnels

Abstract

A transition tunnel is generally built to connect a TBM tunnel and a drill-and-blast tunnel, given the different cross sections associated with each construction method. The transition tunnel may be sensitive to earthquake damage due to the fact that the tunnel cross-section and stiffness change along the tunnel axis. To study the seismic performance of the transition tunnel structure, a series of shaking table tests are carried out. The transition tunnel model is divided into four regions to consider the change of cross-section. Key technical details of the test setup are presented, with a focus on: layout of the model, cross-sections and stiffness of the four regions, model materials, modeling procedure and sensors’ layout. Based on test results, the acceleration response of the tunnel liner and the dynamic pressure between surrounding rock and tunnel liner are discussed. In addition, the peak acceleration, Arias Intensity, and Fourier spectrum are presented for each of the four tunnel regions, to discuss the influence of the change of the cross-sections and stiffness on the seismic response of the tunnel regions.