Seismic Response of Double Metro Tunnels Built in Deep Soft-Soil

Abstract

Rapid development and urbanization have led to the use of underground structures along the world for a wide range of applications including tunnel for subways, railways, highways, material storage, sewage and water transport. The safety of these facilities during seismic events such as recent earthquake in Japan, Taiwan and Turkey becomes more and more problematic due to the complex soil-structure interaction (SSI). The major factor causing severe damages to metro structures is the large deformations imposed by surrounding soils. Thus, for a subway tunnel structure embedded in the soft soil, the study of nonlinear dynamic response of soil-structure interaction during earthquake is important. Nowadays, numerous tools of Finite Element (FE) analysis has been developed to simulate and analyse the tunnel behaviour in order to mitigate its damages during seismic events. In this paper, the displacement response of double metro tunnels under two different earthquake waves is investigate using a Finite Element program (ABAQUS) in 2D plane strain condition, by means of nonlinear dynamic behaviour of soil and tunnels in three different working conditions by varying the embedded depth of the tunnels in soil. The results show that the displacement response of double tunnels built in soft soil is related to the characteristics of the input ground motion, the nature of surrounding soil and the buried depth of the tunnel structures, the peak ground acceleration (PGA) and the SSI effect has an important influence on the displacement response of tunnel structures.

Keywords: double metro tunnels, soft soil, nonlinear, dynamic analysis, ground motion, displacement response, SSI, FE, PGA, ABAQUS

DOI: 10.7176/ISDE/12-2-04

Publication date: June 30^th 2021