Abstract

The aim of this study is to develop coupled matrix formulations to characterize the dynamic interaction between the vehicle, track, and tunnel. The vehicle–track coupled system is established in light of vehicle–track coupled dynamics theory. The physical characteristics and mechanical behavior of tunnel segments and rings are modeled by the finite element method, while the soil layers of the vehicle–track–tunnel (VTT) system are modeled as an assemblage of 3-D mapping infinite elements by satisfying the boundary conditions at the infinite area. With novelty, the tunnel components, such as rings and segments, have been coupled to the vehicle–track systems using a matrix coupling method for finite elements. The responses of sub-systems included in the VTT interaction are obtained simultaneously to guarantee the solution accuracy. To relieve the computer storage and save the CPU time for the large-scale VTT dynamics system with high degrees of freedoms, a cyclic calculation method is introduced. Apart from model validations, the necessity of considering the tunnel substructures such as rings and segments is demonstrated. In addition, the maximum number of elements in the tunnel segment is confirmed by numerical simulations.

Highlights

  • Railway tunnel, as a kind of underground passageway for moving vehicles, plays important roles in shortening the line, reducing the slope, improving the operating conditions, and promoting the traction capacity

  • The aim of this study is to develop coupled matrix formulations to characterize the dynamic interaction between the vehicle, track, and tunnel

  • The physical characteristics and mechanical behavior of tunnel segments and rings are modeled by the finite element method, while the soil layers of the vehicle–track–tunnel (VTT) system are modeled as an assemblage of 3-D mapping infinite elements by satisfying the boundary conditions at the infinite area

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Summary

Introduction

As a kind of underground passageway for moving vehicles, plays important roles in shortening the line, reducing the slope, improving the operating conditions, and promoting the traction capacity. To model track-tunnel systems with consideration of the structural details, finite element method is practically the most useful tactics It significantly increases the degrees of freedom (DOFs) of the dynamic system, thereby reducing the computational efficiency. Aiming at the aforementioned issues, this work contributes to developing a more complex VTT dynamic model by coupling the vehicle, the track and the tunnel as an entire system, where the track-tunnel system is modeled by the finite element method (FEM) and the soil around the tunnel is modeled by the infinite element method (IEM) In this model, the detailed configuration of the tunnel is considered, and the solving method for obtaining the system response with improvement of the computational efficiency is presented. (4) In Sect. 5, conclusions are drawn from the studies

Modelling of vehicle–track–tunnel dynamic interaction
Dynamic equations of motion for the VTT interaction systems
Finite elemental matrix for tunnel segments
Z 1 Z 1 Z 1
À 2ut 2ð1 À utÞ e3
Modelling of the soil around the tunnel
Solution for the VTT dynamic interaction
Improved cyclic calculation method for VTT dynamic solutions
Modeling framework for the VTT dynamic interaction
Numerical study
Validation of the cyclic calculation solution
Comparisons with the wheel-rail elastic contact solution
Influence of segment element number on VTT system performance
Influence of VTT coupling effects on system responses
Findings
Conclusions

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