Influence of seismic loading on segment opening of a shield tunnel.

Yang Chun-Shan,Mo Hai-Hong,Wang Yi-Zhao,Chen Jun-Sheng

doi:10.1155/2014/387210

Yang Chun-Shan, Mo Hai-Hong + Show 2 more

Open Access

https://doi.org/10.1155/2014/387210

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Abstract

The influence of seismic loading on segment opening of a shield tunnel was explored using the dynamic finite element method to analyze the distribution of segment opening under multidirectional seismic loading, combined with a typical engineering installation. The calculation of segment opening was deduced from equivalent continuous theory and segment opening was obtained through calculations. The results show that the scope of influence of the foundation excavation on segment opening is mainly resigned to within 5 segment rings next to the diaphragm wall and 4 joints nearest the working well when the tunnel is first excavated followed by the working well in the excavation order. The effect of seismic loading on segment opening is significant, and the minimum increase of the maximal segment opening owing to seismic loading is 16%, while that of the average opening is 27%. Segment opening under bidirectional coupled seismic loading is significantly greater than that under one-dimensional seismic loading. On the basis of the numerical calculations, the seismic acceleration and segment opening caused by seismic action were normalized, and a new calculation method was proposed for predicting the maximal segment opening of a shield tunnel at different depths under conditions of seismic loading.

Highlights

Subway shield tunneling constitutes a major segment of the civil infrastructure that serves public transportation [1, 2]
[12,13,14] conducted experimental studies of the response characteristics and mechanisms of earthquake damage to utility tunnels. Most of these studies considered only the lateral shear wave of an earthquake and tended to focus on the mechanical characteristics of the lining structure, while studies on seismic response from the standpoint of multidirectional earthquake action and segment opening caused by seismic loading are much less common
A numerical analysis method was conducted by commercial FE software to couple seismic effects to equivalent continuous theory, so that segment opening caused by seismic loading could be more accurately predicted, and to provide a reference for seismic design of shield tunnels

Summary

Introduction

Subway shield tunneling constitutes a major segment of the civil infrastructure that serves public transportation [1, 2]. Researchers have used a variety of approaches, including numerical and analytical methods as well as experimental studies, to explore the seismic response of shield tunnels. [12,13,14] conducted experimental studies of the response characteristics and mechanisms of earthquake damage to utility tunnels Most of these studies considered only the lateral shear wave of an earthquake and tended to focus on the mechanical characteristics of the lining structure, while studies on seismic response from the standpoint of multidirectional earthquake action and segment opening caused by seismic loading are much less common. A numerical analysis method was conducted by commercial FE software to couple seismic effects to equivalent continuous theory, so that segment opening caused by seismic loading could be more accurately predicted, and to provide a reference for seismic design of shield tunnels

Finite Element Modelling

Results and Analysis

C Horizontal displacements of wall body

Prediction Method of the Maximal Segment Opening under Seismic Loading

Conclusions