Underground Grew Up Tunnel Construction Ventilation Were Studied

The drill-blasting excavation is the main economic and efficient means in the construction of large scale underground tunnel. One of the key technical issues—ventilation during construction of underground tunnel affects the entire construction schedule and the safety of construction. The ventilation after blasting is the main task of the construction ventilation. Required to the Air volume calculation of exhaust blasting fumes is the principal basis of the design of Air volume calculation. The calculated result directly affects the identification of air volume and the economic rationality of construction ventilation. Mining, Railways, roads, hydropower and other departments used many air volume formula, although has its theoretical foundation, but it's mainly derived from the experiment. Because of the different experimental conditions and experimental considerations focus on different reasons the same conditions using different formulas calculate the results varied considerably. Therefore, the research on underground tunnel construction ventilation has important theoretical and practical significance .This paper based on the already research results and in conjunction with the Construction of Xiao wan Hydropower Station. And some important conclusion is made.Firstly, This Paper compares and analysis the formula for the air volume calculation of pressure ventilation on domestic and international. And come to the result that in the pressure ventilation of construction should be used B.H. formula for air volume calculation.Secondly, This Paper derived the effective absorption distance's theoretically calculation formula from plane fluid flow theory. And analysis the factor of effective absorption distance by the least square method, from that we know the relationship between thermal vacuum and convection layered length. Under the experimental and theoretical analysis derived the formula of general sense effective absorption distance calculation and exhaust ventilation air volume calculated, the calculated results inosculate the test results. It has important reference value to the calculation formula for exhaust ventilation design and practice.Thirdly, This Paper made some exploratory research to the press out ventilated. Application the least squares method to analysis the experimental results t, come out of the press out ventilated blasting fumes concentration and time attenuation relationship. According to the experiment results derived from the ventilation air volume formula of the press out ventilated. The result of the fitting-out press out ventilated formula is basic agreement with B.H. exhaust ventilated formula. The difference is that the press out ventilated formula considers the ventilation system air leakage rate effects, it does agree with the actual situation.Lastly, This paper based on the optimization theory of ventilation makes a designed to a 2378m Single entry tunnel.