Long Tunnel Construction Ventilation System Optimization Research And Application

The drill-blasting construction is the main economic and efficient technology in the construction of one ended large scale tunnel. One of the key technical issues—ventilation during construction of tunnel affects the construction schedule. It seriously affects the health of workers and labor productivity, if the smoke exhaustion does not achieve the desired limit. The dissertation took the drill-blasting construction ventilation system of one ended large scale tunnel as research target. Using the tunnel construction ventilation theory, the aerodynamics theory and the optimization of the ventilation system theory, it focuses on the construction ventilation system optimization of one ended large scale tunnel. Based on the already research results, some important conclusion of the dissertation is made.Firstly, the paper compares and analysis the ventilation requirements of the drill-blasting construction technology and Tunnel Boring Machine construction technology. And come to the result that the drill-blasting construction more difficult than Tunnel Boring Machine construction in the ventilation technology.Ventilation methods is summarized. And compares and analysis the duct-ventilated methods, and come to the result that the two-way tube composite ventilation method is able to improve work condition in hole.Secondly, the paper establishs the mathematical model of the one ended tunnels ventilation system design. Applying this model to Analyse on the four types of the one ended tunnels ventilation system design and determine calculation method, including same flow fan but differnet wine tube, same wine tube but different flow fan, ventilation distance of single flow fan and severalflow fans working in series.Thirdly, the paper compares and analysis the law of effective fresh wind of the two-way tube composite ventilation and common composite ventilation. Determined the wind amount of the two-way tube composite ventilation by analysed. According to the analysed experimental data, determined the reasonable parameters of ventilation, it is important reference value to the two-way tube composite ventilation design and practice.Lastly, according to the theory of the optimization design of stepped ventilation, this paper will achieve the purpose of energy saving. The subsection number and tube diameter are determined. Combining the stepped ventilation method, applying the mathematical model of the one ended tunnels ventilation system design to calculate, and taking the two-way tube composite ventilation method to optimal design of the first period of the 1# tailrace tunnel construction ventilation of underground powerhouse of xiaowan hydropower station, it saves 47,500 yuan comapring with the traditional design method.