The Technique Research Of Ventilation And Disaster Prevention In Large Underground Interchange

With China's rapid economic development and rapid development of urban road traffic, transportation infrastructure extension to the underground, and large-scale underground interchange hub also with the increasing development. It has some features such as releiving traffic pressures, insuring the fast and smooth traffic of city, improving the traffic environment. With the increase of its size and length, ventilation and disaster preparedness operations become one of the success construction and safe operation of tunnel controlling factors. At present, the experience of domestic ventilation construction and operating for large underground interchange hub is little.This paper discusses control index of pollutants concentrations for the large underground interchange tunnel and the spread law of smoke when on fire within the underground interchange; proposes the applicable conditions of various ventilation in the large underground interchange tunnel, also proposes when the difference of ventilation load between the holes around in the large underground interchange tunnel is large, the air exchange station can be set inside for the longitudinal ventilation optimization program; expounds the design and operations management approach for air flow in the large underground interchange tunnel by ventilation network theory, obtains the air flow characteristics of the bifurcation and the local loss coefficient through the numerical simulation of the bifurcation; verify the validity of the numerical simulation results, shows the manifestations and factors on the air flow of the bifurcation tunnel through physical model tests.This paper combines services, traffic flow characteristics, and the bifurcation structure type of the large underground interchange, uses the successful experiences from abroad combined with theoretical analysis, computer simulation and physical model tests in a comprehensive way, studys on the operation ventilation issues of the large underground interchange hub systematically, provides a theoretical basis for the selection of bifurcation structure type and the air flow design of the ventilation system of the large underground interchange tunnel, provides reference and consultation for the operation ventilation and disaster prevention technology for the large underground interchange in our nation.