Field measurements of aerodynamic pressures induced by suburban rail transit train passing through double-track tunnel with mid-partition wall

Suburban rail lines, which provide fast connections between city centre and the surrounding suburbs, are attracting more and more attention from cities. As a train passes through the tunnel quickly, it tends to produce significant aerodynamic effects. In this study, a series of field measurement experiments were carried out in two tunnels with the mid-partition wall. The influence of train speed and tunnel length on the aerodynamic pressure was analysed. The aerodynamic pressure in adjacent tunnel was also discussed. Furthermore, the attenuation law and coefficient of aerodynamic pressure in tunnels with mid-partition walls were discussed. On this basis, a theoretical calculation model for predicting the peak positive pressure inside tunnels with different lengths and attenuation characteristics was established. The results show that the tunnel length not only affects the amplitude of the pressure, but also significantly affects the distribution trend of the pressure peak in the longitudinal direction. The propagation and reflection processes of pressure waves also exist in the adjacent tunnel on the other side of the partition, and they are synchronous. For the horse-shaped tunnel with mid-partition walls, the peak pressure inside the tunnel is directly proportional to the 2.05–2.20 power of the train speed, and the peak pressure decays exponentially with time. The pressure attenuation coefficient is greatly influenced by the placement of the measuring point, ranging from $4.957 \times {10^{ - 5}}$4.957×10−5 to $8.184 \times {10^{ - 5}}$8.184×10−5 depending on the position of the measurement point. This work provides important data support for studying the tunnel aerodynamic effects and verifying related numerical simulations.