Numerical modelling of a tunnel adjacent to a surface structure in liquefiable ground

Abstract

Earthquake-induced liquefaction is likely to cause uplift displacements of underground structures and excessive settlements of surface structures. While these two phenomena have been investigated separately in the literature, the case of a shallow tunnel buried adjacent to a surface structure in liquefiable ground has not yet been thoroughly studied. In this paper, the OpenSees platform is employed to numerically model two centrifuge tests on the structure–soil–structure interaction in saturated Hostun sand. The PM4Sand constitutive model is calibrated to capture the non-linear behaviour of the liquefiable ground. Overall, the numerical simulations are in good agreement with the centrifuge test data. The excess pore pressure build-up, the acceleration response of the Hostun sand ground, the uplift of the tunnel and the settlement of the surface structure are simulated with adequate accuracy. Then, the validated numerical models are used to investigate further the structure–soil–structure interaction in liquefiable ground, with a special emphasis placed on the variation of the relative density of the sand, and a parametric analysis is conducted on the responses of the tunnel and the surface structure.