| The study on natural wind pressure, which includes investigation of meteorogical data and calculation of temperature in tunnels, must be conducted in ventilation design of tunnel with ventilation shaft, especially for the long or super-long tunnel with many high shaft. Niba Mountain Tunnel with complex topography and geomorphology and meteorological conditions is a deeply buried super-long highway tunnel. The ventilation is very difficult for the super-long tunnel originally. It is more difficult to determine the natural wind of each section on tunnel with ventilation shaft. In order to determine natural wind of each section on tunnel, meteorological conditions of surrouding tunnel must be monitored for a long term.Niba Mountain Tunnel, up to10km, is a controlling engineering of expressway from Ya'an to Luzhou. Based on Niba Mountain super-long highway tunnel, combined with the project of key technology research on a deeply buried super-long tunnel--Daxiang Valley-Niba Mountain Tunnel (2006318000104) supported by the China Western Communications Construction Scientific and Technological Project, such aspects as influencing factors to natural wind, calculation method of natural wind on each section and energy saving ventilation technology have been analyzed and studied systematically and thoroughly, by different research means such as data investigation, theoretical analysis, in-situ measurement, long-term monitoring, programming and numerical simulation.What this paper mainly discusses lies in the following areas:(1) In view of the meteorological data and the investigation data of weather station and in-situ measurement, the influencing factors of natural wind pressure in the super-long tunnel have been analyzed qualitatively. It is obtained that natural wind pressure has been effected by environment of outside, inside of tunnel and the structural opening. The three influencing factors are respectively ultra static pressure difference produced by atmospheric horizontal pressure gradient, ventilation wall pressure difference produced by blowing of natural wind and thermo-potential difference produced by the diffenence of outside and inside temperature of tunnel.(2)3D calculation model is proposed by numerical simulation method and theoretical calculation formula is derived. By verification on Erlang Mountain Tunnel, Tiefeng Mountain Tunnel and Fangdou Mountain Tunnel, theoretical calculation formula of interal natural wind of tunnel is established.(3) Four long-term weather stations have been built on Niba Mountain Tunnel. Testing parameters includes wind direction, wind velocity, atmospheric pressure, air temperature and air humidity.93120group and465600related data have been obtained. (4) The maximum wind velocity, distribution of wind velocity frequency and quarantee rate have been established. In view of these, a new energy saving design model by natural wind ventilation on deeply buried super-long tunnel is confirmed. Wind direction is from Lugu to Ya'an in Niba Mountain Tunnel. The annual probability from the first to the third section is respectively63.2%,60.8%and61.5%. Wind direction of shaft in Ya'an is air supply and the annual probability is62.0%. And wind Wind direction of shaft in Lugu is also air supply and the annual probability is53.9%.(5) Energy saving design model using natural ventilation efectively under the condition of longitudinal ventilation in deeply buried super-long tunnel is established. That is by controlling wind velocity and wind direction of each section based on setting energy saving duct and air valve, energy saving ventilation on tunnel has been accomplished. When natural wind and traffic direction is in the same direction and natural wind velocity is faster than design velocity, energy saving duct would be used for ventilation. While natural wind velocity is slower than design velocity, natural wind auxiliary ventilation would be adopted. Using the energy saving model, it would save50.5%by real-time control and13.28%by time block control in Niba Mountain Tunnel.
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