Portal de Periódicos da CAPES

An overview of wave propagation in tunnels

2002; Springer International Publishing; Linguagem: Inglês

10.1007/978-3-540-45854-8_21

1860-0824

A. E. Vardy, Jim Brown,

Geotechnical Engineering and Underground Structures

The propagation of pressure waves along railway tunnels is reviewed with special emphasis on isolated compressive waves such as those generated during the early stages of train entry to a tunnel. Particular attention is paid to the evolution of pressure gradients in the leading regions of the waves — because the gradients just before the tunnel exit determine the strengths of micro-pressure waves that are the focus of attention in TRANSAERO Work Package 4.1. The physical phenomena considered herein are (i) inertia, (ii) skin friction, both quasi-steady and unsteady, and (iii) the compliance of air trapped between aggregate elements in ballast track tunnels. It is shown that the first of these tends to cause steepening of wavefronts and that the others tend to cause flattening. Skin friction is found to have a strong influence on pressure amplitudes as well as on pressure gradients.