Research On Numerical Simulation And Automatic Control Technology Of Tunneling Ventialation

Construction ventilation is the key factor for tunnel construction in tunneling. Based on the practice of construction ventilation in Guanhuchong tunnel and the general problems existing in tunnel construction ventilation, this thesis analyzes the diffusion effect of hazardous gas in double tube tunneling construction by using Numerical Simulation, putting forward automatic control technology in tunneling ventilation, discussing the key technical problems of this technical scheme, which includes the composition and structure of automatic control ventilation system, variable frequency technology of fan, PLC and fuzzy PID control technology, data collection under the environment of tunnel and communication principle. The new research results can be summarized as followed:(1) The result shows that, if the ventilating power of two tunnels is different, CO will diffuse into neighboring tunnel through crossing between two tunnels, after the blasting of heading face of the one tunnel, and the air in the neighboring tunnel is seriously contaminated. This research analyzes the degree of contamination produced by hazardous gas in different zones of the tunnel. The more practical as well as suitable ventilation managements were proposed, according to the research of the impact of CO diffusion that was aroused in the equal ventilating power of two tunnels after blasting.(2) It realizes automatic control in tunneling ventilation, and programs corresponding control language, which can give specific control command after analytical judgment according to the data transmitted by various sensors. And the workflow of this program can be presented as followed:sensors monitoring the onsite data constantly, conducting data collection and conversion through PLC, making contrast analysis with the set value after uploading the data to control software, adjusting the operation parameters of fan according to the preset value, giving control command, regulating the fan through the execution unit of frequency converter, thus forming one control process, then feeding back the actual result of last regulation based on the second data collection through sensors, beginning a new round of adaptive control process, thus realizing closed-loop control in automatic control of fan.(3) In combination with the onsite application effect of automatic control system in tunneling ventilation, it formulates the construction method of automatic control construction, mainly consisting of the construction of ventilation control system, calculation of ventilation parameter, construction safeguard measures, technical specification and requirements, equipment selection and software debugging, system maintenance and so on.