Analysis on the Influence of Increasing Seismic Fortification Intensity on Seismic Performance of Underground Station

Ying Zeng,Shiguang Xu,Shiqian Yin,Lingkun Chen

doi:10.1155/2021/8158607

Abstract

China Earthquake Parameter Zoning (2016) has increased the seismic fortification intensity in Chengdu from VII to VIII. It is necessary to conduct in-depth discussion on the impact of the seismic performance of the built underground station structure. In this paper, a stratum-structure finite element model is established with a Chengdu subway station as an example. The model boundary adopts viscoelastic boundary, and the ground motion is input in the form of equivalent nodal force. The equivalent linearization method is used to consider the nonlinearity of soil materials. The time-history analysis of seismic fortification intensity of VII and VIII degrees is carried out, respectively. By comparing the calculation results of the two seismic fortification intensity ground motion conditions, it is concluded that the connection between the side wall and the floor is the weakest position of the station structure under the action of the earthquake; the seismic fortification intensity is increased from VII to VIII to the internal force of the structure. It has a relatively large impact, especially the most obvious impact on the bending moment. The results of the verification of the seismic time-history analysis show that the increase of fortification intensity will have a more obvious impact on the structural deformation, and the structural design of the station can meet the safety performance requirements of VII and VIII degrees of seismic fortification. The research has certain reference significance for the seismic safety evaluation of the built underground station structure in Chengdu area.

Highlights

With the development of science and technology and productivity in China, more and more underground structure projects are emerging and the research on their seismic performance is paid more and more attention [1]
Is paper takes an underground station of the Chengdu Metro as an example, adopts the viscoelastic boundary and equivalent nodal force input method of ground motion, uses the equivalent linearization method to simulate its nonlinearity in the soil material, and, respectively, calculates the VII and VIII earthquake response under the conditions of high seismic fortification intensity, combined with national standards to check the seismic performance of the station structure, discuss the impact of the increase in seismic fortification intensity on the seismic performance of the built subway, and evaluate the seismic safety of the built subway project
According to the “Standard for Seismic Design of Underground Structures” [23], the calculation results are checked for cross-sectional bearing capacity and seismic deformation

Summary

Introduction

With the development of science and technology and productivity in China, more and more underground structure projects are emerging and the research on their seismic performance is paid more and more attention [1]. Wang et al [4, 5] adopted the finite element numerical simulation method, respectively, to establish an analysis model and discuss the influence law of seismic response of underground structures. Is paper takes an underground station of the Chengdu Metro as an example, adopts the viscoelastic boundary and equivalent nodal force input method of ground motion, uses the equivalent linearization method to simulate its nonlinearity in the soil material, and, respectively, calculates the VII and VIII earthquake response under the conditions of high seismic fortification intensity, combined with national standards to check the seismic performance of the station structure, discuss the impact of the increase in seismic fortification intensity on the seismic performance of the built subway, and evaluate the seismic safety of the built subway project

Engineering Background

Result

Experimental results

Conclusion