VENTILATION OPENING 0.25 KILOMETERS LONG, MINIMIZING PRESSURE FLUCTUATION AND MICRO PRESSURE WAVE FOR SHORT TUNNEL USE

摘要

PURPOSE: A ventilation opening 0.25 kilometers long minimizing pressure fluctuation for a short tunnel use is provided to decrease pressure fluctuation up to 50percents by determining the distance, the number and the diameter of a ventilation opening, also decreasing micro-pressure wave up to 40%. CONSTITUTION: Generally, when a train enters a tunnel, a pressure wave generates and the pressure wave gets transmitted into the inside the tunnel, then a micro-pressure wave radiates from an exit. The micro-pressure wave is considered to be a shock wave, therefore causing vibration and damaging neighboring things as well as internal organs of a human being. Consequently as a way of reducing the effect of a micro pressure wave, the idea of installing ventilation openings is applied with a statistical analysis, according to the length, the diameter of a tunnel. Most of all, the number of ventilation openings influences decrease or increase in a micro-pressure wave. According to the test data, a tunnel with 28 square meters and 0.25 kilometers long needs 12 ventilation openings to decrease a micro-pressure wave up to 40%.