Abstract: In order to demonstrate the theoretical phenomenon of the aerodynamic effects induced by high-speed trains in tunnels, and to verify the numerical simulation and the pressure criteria at design stage, the field measurements in the two longest tunnels of Taiwan High Speed Rail (THSR) were performed at several train speeds and different locations. Results show that the aerodynamic effects induced by the THSR trains are consistent with previous studies in literature. The entering of train nose generates a compression wave with a significant pressure rise, and the passage of train produces an immediate pressure drop due to the aerodynamic drag. The peak pressure value is approximately proportional to the speed of the train, reaching to the power of 2.1~2.2. The aerodynamic pressures recorded near the tunnel portal are small in general. At locations inside the tunnel with a distance larger than 50m from the portal, there is similar pressure values. When the train speed is around 220~230km/h, the peak pressure value is about 1.0kPa, and the peak value recorded is about 1.35kPa for a train speed close to 300km/h. All the peak values obtained from the field measurements are still far below the design standard of THSR for tunnel facilities.

Key words: tunnel, aerodynamics, high-speed railway, field measurement, peak pressure value