Effective stress analysis for repeated shake-consolidation process of multi-story buildings in liquefiable soils during sequential earthquakes

Historical data has shown that soil-structure systems exhibit increased severity when subjected to earthquake sequences, attributed to the accumulated instability of soil deposits and the cumulative damage of structures. This study analyzes seismic responses of multi-story buildings and mechanical behavior of liquefiable soil deposits under repeated shake-consolidation process. This is achieved through a series of numerical simulations using a finite element-finite difference (FE-FD) code, namely DBLEAVE-X. Sequential earthquakes are obtained from the NGA-West2 PEER ground motion database and recalibrated relied on various aspect ratios, including peak ground acceleration ratios (rPGA) and consolidation time (Tgap). The numerical results reveal that shearinduced and residual settlements of buildings during sequential earthquakes might be notably larger than that during single earthquakes. The repeated shake-consolidation process has a significant impact on development and dissipation of excess pore water pressure (E.P.W.P), notably influencing the deformation response of both buildings and ground deposits. The findings also provide valuable insights into effects of both complete and partial consolidation processes on seismic mechanisms of entire liquefiable soil-structure systems. Numerical observations suggest that multi-story buildings under sequential earthquakes might be more vulnerable, underscoring the necessity of integrating sequential earthquakes into earthquake-resistant building design.