Full-Scale Experimental Investigation of the Interaction between Trains and Tunnels

Abstract

This works focuses on a series of experimental tests carried out to investigate overpressures in tunnels due to train crossings. Although the above-mentioned topic is well known and also defined in European standards, in the literature full-scale data are lacking, which are useful to validate the numerical codes required in the certification process and are used in train structural dimensioning. In this respect, an extensive full-scale experimental campaign was planned for observing as many test conditions as possible, such as single passages of different trains, two train crossing, different tests speed, and different tunnel characteristics. In detail, the understanding of the pressure wave generation and transmission is deeply enhanced by studying the pressure evolution both on board and at trackside, considering both single train passages or two trains crossings and having the possibility to compare aerodynamic loads on sealed and unsealed trains. Furthermore, the position of sensors, the speed of the train, and the initial conditions within the tunnel have been proven to be fundamental parameters for properly estimating the pressure loads on trains.

General Analytical Method to Predict the Spatial–Temporal Distribution of Extreme Pressure in High-Speed Railway Tunnels in the Post-Train Stage

“…The location and time of the extreme pressure in the tunnel are x and t, respectively. Thus, the issue concerning their position and time of appearance involves six variables, which are L tu , L tr , v tr , c, x, and t, but only two fundamental dimensions, length L and time T. According to Buckingham's π theorem [50], 6 − 2 = 4 dimensionless products are determined, as shown in Equations ( 17)- (20).…”

“…The research methods for investigating pressure waves in tunnels include field measurements [8,14,18,20], moving model tests [13,21,22], numerical simulations [4,23], and theoretical analysis [24][25][26]. However, field measurements and moving model tests are usually expensive and limited by the existing test conditions, and numerical simulations with three-dimensional models consume a lot of computing resources and time [23,[27][28][29].…”

Research@ZaB: Study of FDS Capabilities to Assess the High-Speed Train Impact on Pressure Pattern Within a Railway Tunnel

“…Furthermore, pressure gradients cause train passengers discomfort and occasionally medical problems and can be rather dangerous for tunnel workers and people at a trackside or on a platform. To address this issue, a certain number of studies were conducted to investigate this aerodynamic phenomenon [11][12][13]. The results of this research field became the foundation for standard procedures and the development of the aerodynamic loading limits that were reflected in the Technical Specification for Interoperability and European standard EN 14067 [14,15].…”

Virtual homologation of high-speed trains in railway tunnels: A new iterative numerical approach for train-tunnel pressure signature

“…For HS lines with tunnels, this trend leads to a larger number of trains that cross tunnels during the operational life and moreover a larger number of twotrain crossings occurring inside tunnels. 8 Conventional trains and freight trains are not specifically designed for large overpressure in tunnels, since they are supposed to run on conventional lines at normal speed, and they may encounter problems if they are used in mixed traffic operation on HS lines together with HS trains.…”

“…For HS lines with tunnels, this trend leads to a larger number of trains that cross tunnels during the operational life and moreover a larger number of two-train crossings occurring inside tunnels. 8…”