Seismic response of a segmental tunnel in soil-rock strata: 1g shaking table test

Abstract

The tunnel crossing soil-rock strata is a common scenario in engineering construction, and it is more vulnerable to earthquake impact than that in uniform ground conditions, while related studies on this topic are scarce. This paper investigates the seismic characteristics of a segmental tunnel crossing soil-rock interface by 1g shaking table test. Regarding the ground-tunnel relative stiffness as a dominant parameter, materials of model soil and model rock are selected. A refined model tunnel is designed to reproduce the segmental feature of the prototype tunnel. An artificial earthquake wave is input from the shaking table along the transverse direction. Seismic performances of the model tunnel, including the acceleration, sectional deformation and longitudinal joint extension, are analyzed to evaluate the soil-structure interaction (SSI). The discrepant seismic responses of the tunnel portions in the two different strata are revealed by the acceleration data. Due to the spatial variation caused by the soil-rock ground condition, significant joint extension near the interface and large sectional deformation at the soil deposit are observed, while deformations of the tunnel portion in rock are negligible. This work presents part of the test data, and it could be used to verify the numerical model, which is aimed at analyzing the seismic performance of the very same segmental tunnel in soil-rock strata.