Abstract

In this study, a soil–tunnel model for clay under earthquake loading is analyzed, using finite element methods and a kinematic hardening model with the Von Mises failure criterion. The results are compared with those from the linear elastic–perfectly plastic Mohr–Coulomb model. The latter model does not consider the stiffness degradation caused by imposing cyclic loading and unloading to the soil, whereas the kinematic hardening model can simulate this stiffness degradation. The parameters of the kinematic hardening model are calibrated based on the results of experimental cyclic tests and finite element simulation. Here, two methods—one using data from cyclic shear tests, and the other a new method using undrained cyclic triaxial tests—are used to calibrate the parameters. The parameters investigated are the peak ground acceleration (PGA), tunnel lining thickness, tunnel shape, and tunnel embedment depth, all of which have an effect on the resistance of the shallow tunnel to the stresses and deformations caused by the surrounding clay soils. The results show that unlike traditional models, the nonlinear kinematic hardening model can predict the response reasonably well, and it is able to create the hysteresis loops and consider the soil stiffness degradation under the seismic loads.

Highlights

  • With the growing populations in metropolitan cities around the world, underground urban infrastructure development has become a major focus

  • Previous studies have shown that tunnels located in clay soils are more likely to be damaged by earthquakes than those constructed in sandy soils [11,12,13,14]

  • It is noteworthy that in this research, all the soil–tunnel models were simulated in addition to the kinematic hardening constitutive model using the Mohr–Coulomb model, and the results were in good agreement with the results of a previous study that considered the Mohr–Coulomb model using PLAXIS software

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Summary

Introduction

With the growing populations in metropolitan cities around the world, underground urban infrastructure development has become a major focus If these underground structures are constructed in earthquake areas, their dynamic response to seismic loads must be determined in order to reduce economic damage and threats to human safety. There have been numerous examples in different countries of earthquakes causing extensive damage to underground structures (e.g., the Kobe earthquake, 1995; Taiwan, 1999) [1,2,3,4,5,6,7], which indicates that it is crucial for studies to be made of the seismic behavior of tunnels. There are fewer studies on the seismic behavior of tunnels located in soft soils than in sandy soils Different approaches such as numerical [15,16,17] and

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