Ground-Borne Vibrations Induced by Trains Moving in Underground Tunnels
Date Issued
2006
Date
2006
Author(s)
Hsu, Lin-Ching
DOI
en-US
Abstract
Ground-borne vibrations resulting from the underground railway traffic have become an important environmental issue, which has received increasing attention from both engineers and researchers. In this dissertation, an integrated investigation is conducted of the ground-borne vibration problem induced by trains moving in underground tunnels. Starting from an extensive literature review, practical parameter analyses were carried out for a two-dimensional simulation of the soil-tunnel interaction system, which were then extended to a 2.5D simulation with account taken of the moving effect of the train loads. The numerical procedure adopted here is called the coupled finite/infinite element method. With this approach, a soil-tunnel system is divided into two regions, i.e., the near and far fields. The near field, including the loads and other geometric/material irregularities, is simulated by the finite elements as conventional, and the far field covering the soils with infinite boundary by the infinite elements. This hybrid approach can overcome the inherent drawback of the finite element method in simulating the radiation damping for waves traveling to infinity. On the other hand, it can be established within the framework of the finite element method, which is commonly used by most structure analysis programs and is likely to be favored by most practicing engineers.
From the results of this research, it can be concluded that even in most underground railways systems with the normal operating velocities, the coincidence of the loading frequencies with the fundamental frequency of the soil layer can still result in an apparent increase of the vibration level. Accordingly, to relieve the vibration of this kind, a fundamental solution should be resorted to avoid the coincidence of the loading frequencies of train with the fundamental frequency of soil layer.
Subjects
列車
地下隧道
土壤振動
無限元素
train
underground tunnel
ground-borne vibration
infinite element
Type
thesis
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