Experimental investigation of the seismic response of shallow-buried subway station in liquefied soil

摘要

In this study, a series of shaking table tests were carried out based on an irregular cross-section subway underground structure. Further, the development laws of pore pressure, structural strain, acceleration intensity, and the propagation law were analyzed. The results show that the peak acceleration of the surface is attenuated, which reflects the isolation effect of the liquefied soil. The spectral characteristics of the liquefied foundation soil reflect the low frequency band concentration and amplification effects. Moreover, there is a significant floating phenomenon in the model structure during the earthquake. With an increase in the degree of liquefaction at the site, the uneven settlement and slope of the variable-section underground structure become more significant. The dynamic strain on each member of the structure shows that the middle column has the largest reaction, the sidewall is the second largest, and the floor has the smallest; the bottom end of the lower middle column is most vulnerable to damage. A modified dynamic constitutive model was used for soil; the rate-independent plastic-damage constitutive model was used for concrete in the numerical simulations using the finite element method. The difference between the results obtained by numerical analysis and shaking table tests is discussed in detail. The results provide insight into how strong ground motion may induce the liquefaction of soil.