Experimental analysis and evaluation of a new seismic isolation method for subway stations in the Loess Plateau with localized sand-interlayered strata

Abstract Post-earthquake statistics indicate that the existing seismic measures and evaluation methods for subway stations in the Loess Plateau with locally interbedded sand layers are inadequate. During earthquakes, the station roofs are prone to deformation or even failure, posing a serious threat to station safety. Therefore, the primary objective of this paper is to propose a new seismic mitigation method for subway stations in the Loess Plateau with locally interbedded sand layers, thereby addressing the structural seismic issues of such stations. Using a specific subway station in Xi’an’s rail transit system as the engineering context, this method employs the geometric scale of 1/50 to systematically analyze the deformation and failure characteristics, acceleration response, and bending moment patterns of the station equipped with an EPE foam board seismic isolation layer under a 0.35 g horizontal seismic load. It reveals the dynamic response and mechanical evolution characteristics of the station and its surrounding loess, and evaluates the effectiveness of the EPE foam board seismic isolation layer in enhancing the seismic performance of the subway station. The results indicate that the EPE foam board damping layer effectively reduces peak acceleration at all measurement points, with reductions ranging from 13.95 to 14.02%; The extreme values of bending moments at all measurement points were significantly reduced, with the maximum reduction reaching 36.22%. Simultaneously, the stress concentrations of the tensile stress zones in subway station were effectively alleviated, the seismic isolation measures resulted in the optimization of the overall dynamic response of the subway station, and the seismic performance of the station was enhanced. Furthermore, this vibration-damping layer exhibits good damping performance, features a simple construction, is economical, durable, and wear-resistant, and involves convenient construction techniques, making it suitable for widespread application. The research findings hold significant reference value for the design, construction, and safe operation of subway stations in loess region.