Objective  The train internal/external pressure wave variations of Hangzhou Metro Line 19 Phase I project are analyzed and studied during operation at a speed of 120 km/h in the tunnel. Specific and reasonable guiding suggestions are provided for controlling of tunnel pressure wave variations in actual engineering construction.

Method Through a combination of numerical calculation and field measurement, the pressure waves generated when metro trains run in the tunnel or enter the tunnel from the open track are simulated. The influences of tunnel diameter, blockage ratio, train air-tightness, and tunnel entrance pressure relief structures on the high-speed tunnel pressure waves are compared and analyzed.

Result & Conclusion  When the tunnel diameter increases from 6.0 m to 6.1 m, the maximum change rate of internal pressure is reduced by approximately 4.2%; when the tunnel diameter increases from 6.1 m to 6.2 m, the above maximum change rate is reduced by approximately 2.4%; but when the tunnel diameter is 6.1 m or larger, the further increased tunnel diameter has limited effect on pressure variation reduction both inside and outside the train. When a fully enclosed acoustic barrier pressure relief structure is installed at the tunnel entrance, the maximum change rate of train internal pressure is reduced by approximately 40% ~50%. The calculation and measured results of the most unfavorable sections in this project show, that the internal pressure changes significantly when the train passes through the section ventilation shaft, and measures such as optimizing the piston ventilation shaft area or setting piston dampers should be adopted to reduce the magnitude of pressure variations.