Pressure-Wave Studies in the Tunnel-Simulation Facility Göttingen (TSG)

When a high-speed train enters a railway tunnel, a complicated system of pressure waves is generated, which comes along with many disadvantages. The abrupt pressure changes lead to loads on the structures of train, tunnel and on the installed equipment of the tunnel. Additionally, the pressure waves can steepen, which can end in the so-called tunnel-boom. The passengers of the high-speed trains are affected by the pressure changes as well. Therefore modern high-speed trains are sealed, but this requires extra weight and thus a higher power consumption. To investigate the pressure wave generation experimentally in model scale the tunnel-simulation facility G\"ottingen (TSG) was built in 2010. It represents a moving-model rig with train models, that can be accelerated up to a velocity of 100m/s. The train velocity can be adjusted stepless by regulating the hydraulic pressure with an accuracy of less than 1%. The facility is equipped with a model tunnel with a length of 10m, which can be easily extended. Experiments were conducted in the new facility with a 1:25-scaled model of the german high-speed train ICE3. The pressure-time history of experiments with and without extended tunnel portal reveals, that the slope of the pressure can be influenced by the shape of the tunnel hood. The first pressure rise begins earlier and the gradient is smaller than without hood. It is further shown, that the pressure gradient can be reduced by about 45% using an extended, vented tunnel portal. The new facility provides the opportunity to study the pressure characteristics while a train passes a tunnel with very high repeatability and reproducibility. The facility allows a realistic investigation of the train-tunnel interaction and of pressure-wave induced forces on trackside objects during the passage of a train