TY - JOUR
T1 - Influence of air chambers on wavefront steepening in railway tunnels
AU - Liu, Feng
AU - Vardy, Alan E.
AU - Pokrajac, Dubravka
N1 - Funding Information:
The authors are grateful to the following bodies that provided financial support for the project: (a) National Natural Science Foundation of China (grant no. 52002265), (b) China Scholarship Council (201806935055), (c) State Key Laboratory of Traction Power (grant no. TPL1904), (d) Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (grant no. 2019L0251), (e) Natural Science Foundation of Shanxi Province, China (grant no. 201801D221224).
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/11
Y1 - 2021/11
N2 - The behaviour of wavefronts propagating in a tunnel with multiple, compact air chambers is investigated with particular reference to the suppression of unacceptable pressure disturbances radiating from exit portals. Attention is focussed primarily on chambers that respond in an over-damped manner to pressure variations in the tunnel. In the early part of the paper, comparisons are made between the qualitative behaviour of wavefront propagation in tunnels with and without air chambers. Thereafter, attention turns to a quantitative assessment of the influence of key design parameters, especially the chamber volume and properties of connectors between chambers and the tunnel. It is shown that the optimum type of connector depends upon the length of the tunnel along which the chambers exist. For short tunnels, relatively low-resistance connectors with linear pressure:flow rate characteristics are preferred, whereas for long tunnels, relatively high-resistance connectors with quadratic pressure:flow rate characteristics are likely to be more suitable. Brief attention is paid to the practical feasibility of creating suitable connectors.
AB - The behaviour of wavefronts propagating in a tunnel with multiple, compact air chambers is investigated with particular reference to the suppression of unacceptable pressure disturbances radiating from exit portals. Attention is focussed primarily on chambers that respond in an over-damped manner to pressure variations in the tunnel. In the early part of the paper, comparisons are made between the qualitative behaviour of wavefront propagation in tunnels with and without air chambers. Thereafter, attention turns to a quantitative assessment of the influence of key design parameters, especially the chamber volume and properties of connectors between chambers and the tunnel. It is shown that the optimum type of connector depends upon the length of the tunnel along which the chambers exist. For short tunnels, relatively low-resistance connectors with linear pressure:flow rate characteristics are preferred, whereas for long tunnels, relatively high-resistance connectors with quadratic pressure:flow rate characteristics are likely to be more suitable. Brief attention is paid to the practical feasibility of creating suitable connectors.
KW - Air chambers
KW - Micro-pressure waves
KW - Rail tunnels
KW - Wavefront steepening
UR - http://www.scopus.com/inward/record.url?scp=85113274195&partnerID=8YFLogxK
U2 - 10.1016/j.tust.2021.104120
DO - 10.1016/j.tust.2021.104120
M3 - Article
AN - SCOPUS:85113274195
SN - 0886-7798
VL - 117
JO - Tunnelling and Underground Space Technology
JF - Tunnelling and Underground Space Technology
M1 - 104120
ER -