| As increasing number of long tunnels have been built, researches of ventilation technology in long tunnels have become more and more important, for they are key safeguards for tunnel. Accordingly, this paper systematically carries on researches on this field and establishs an analysis method of tunnel ventilation which is based on Network theory. Ventilation mechanism in tunnels, especially natural ventilation mechanism, has been analyzed as well.Firstly, according to tunnel characteristics, a method is introduced to establish tunnel network. It is used to develop software for ventilation calculation. The components of tunnel network are defined and the concept of "edge node" is applied to describe the relationship between air in tunnel and surrounding.Secondly, air heat transfer in tunnel has been studied and a theoretical model for calculating attributes of network edges. Considering influnces of tunnel surrounding, vechical exhausts and vent pressure, a model which reflects these influences is used to study tunnel ventilation.Thirdly, a network model, which include a subordinal fluence model, a subordinal temperature model and a subordinal heat pressure model. In the heat pressure model, temperature matrixes which are the mathametical base of the software have been introduced and independence of relative formulas of matrixes has been proved.Forthly, framework of ventilation software is established. At the same time, a program which is used to calculate required fresh air has been made. With these softwares, tunnel ventilation can be analyzed.Finally, natural pressure of tunnels with single shaft and tunnel with two shafts are studied with the software. According to the result of natural pressure which is offered by the software, the influence of ratio, the height of shaft and air temperature have been analyzed. |
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