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| Influence of High Rock Temperature and Low Pressure on Piston Wind for Tunnels in High Altitude Plateau |
| SUN San -xiang, ZHAO Shou, ZHANG Yun –xia |
| (Lanzhou Jiaotong University，Lanzhou，Gansu 730070，China) |
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Abstract Abstract ：Research purposes： The Qinghai - Tibet railway line in china, characterized with low barometric pressure, is the highest altitude railway in the world at present. Numbers of hot and boiling springs can be seen along the railway line. During tunnel operation， because of the long - standing puzzles of special conditions， the effects of the high altitude，high rock temperature and low pressure on tunnel piston wind needs to be further studied urgently. Research conclusions ： The three - dimension dynamic grid model was established by using the finite element software ANSYS/CFX14. 0. The model proved to be validity by the experimental data. Furthermore， the standard k - s turbulence model and Reynolds - averaging equations were employed to numerically simulate the influence of high rock temperature and low pressure on pressure coefficient of piston wind when single trains through the tunnel with variable speed. The results show that:(1) If the heat flux on the tunnel wall is less than 30 W/m2，its impact on the pressure coefficient is very little and could be neglected. (2) Compared with the standard atmosphere pressure 1.0 atm， the barometer pressure of 0. 562 5 atm on the high plateau shows no influence on the pressure coefficient of the tunnel piston wind. (3 ) The study results improve the calculation theory piton wind under the conditions of high altitude, high rock temperature and low pressure， and give guidance for the piston wind calculation of the special highland climate conditions of Qinghai - Tibet railway.
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Received: 18 January 2016
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2016, Vol. 33 
