Seismic response analysis for induced joints of subway station in loess area

Since the introduction of the concept of induced joints in subway station structure in the 1990 s, induced joints have been extensively employed in the subway station in large and medium-sized cities in China. However, the seismic performance of induced joints remains unverified. The construction of a subway station in the loess area of Xi'an was taken as the research background. The three-dimensional numerical simulations on the dynamic interaction between the loess site and the subway station structure were conducted using the ABAQUS® nonlinear finite element software program. The reliability of the numerical model and analysis method was verified by comparing the numerical simulation results against those of the shaking table tests. Based on the above numerical methods, the numerical calculation model of prototype structures was further established to study the seismic responses of the induced joint of subway station in loess site under the action of seismic waves with different spectrum and peak acceleration characteristics. The results show that the cross sections of induced joints are more easily destroyed during an earthquake. The horizontal relative slips between both sides of the induced joint increase from the bottom to the top of the structure. The vertical relative displacement of the structures on both sides of the induced joint shows a pattern of larger at both ends and smaller in the middle along the width direction of the subway station section. Under the action of Xi ’ an artificial waves with abundant low- frequency components, the plastic deformation of the remaining longitudinal rebar in the cross section of induced joints develops throughout the entire process of seismic action, and the accumulative effect of the plastic deformation is more significant. The research results preliminarily reveal the seismic response characteristics and rules of subway stations with induced joints, which has certain reference value for further exploring the internal dynamics and mechanisms of structural damage and failure development of subway stations with induced joints under earthquake action. It can provide references for the seismic design of underground structures with induced joints in loess area. © 2024, Central South University Press. All rights reserved.