Investigation of the liquefying characteristics of saturated loess surrounding tunnels under seismic loading based on large-scale shaking table tests

Abstract

This study investigates the liquefaction potential of saturated loess surrounding tunnels in the Loess Plateau region and the effect of loess liquefaction on tunnel seismic response. A large (1:20 scale) shaking table model was designed and built to replicate a tunnel that is under construction on the Lanzhou–Hezuo Railway in China. Shaking table tests were then conducted using local time-history records of strong earthquake acceleration. The saturation loess surrounding the tunnel model did not liquefy under the seismic motion induced by the seismic precautionary intensity. However, loess surrounding the tunnel liquefied before the soil far from the tunnel. The effects of loess saturation, loess liquefaction, and the presence of the tunnel structure on seismic intensity (either amplification or attenuation) were also analyzed, and the variations of unsaturated and saturated loss before and after seismic motion were discussed. The findings provide a reference for the seismic design and construction of tunnels where the surrounding loess is or will likely be in a saturated state.