Abstract: The underground structures in saturated liquefiable soils may be subjected to floatation due to earthquake induced liquefaction. After earthquake, the excess pore pressure shall dissipate and the liquefied soil will experience the process of consolidation. The post-earthquake behavior of underground structures in liquefiable soils is not clear and deserves investigation. Nonlinear coupled dynamic finite element method was used to investigate the response of the liquefiable soil-underground structure system, focusing on the vertical displacement of the underground structure. It was found that the uplift behavior of the underground structure did not cease to develop when the earthquake stopped; instead, it terminated after the excess pore pressure was dissipated to some extent and the underground structure started to settle afterwards, but with a magnitude much smaller than the amount of uplift. Residual deformation existed in the underground structure after earthquake. The stress path, the process of excess pore pressure dissipation, and the effects of cutoff walls and coefficients of permeability were also discussed, in an effort to tackle the mechanism of the post-earthquake response of underground structures in saturated liquefiable soils.

Key words: underground structures, earthquake induced liquefaction, consolidation, residual deformation