Analysis on ventilation and pollutant emission at entrance of Honggu Tunnel in Nanchang

Through the calculation of tunnel air demand, ventilation network simulation and field wind speed test, obtains the ventilation volume of each ramp in the tunnel under different vehicle speed conditions. Analyses the multi-ramp air rate distribution characteristics. By means of the TOP mode of pollutant diffusion at tunnel exit, predicts the pollutant diffusion at tunnel exit under different air rate conditions. Measures the pollutant concentration at tunnel exit and analyses the impact of exhaust air at the tunnel exit on the environment near sensitive buildings. The results show that the base emission value of CO is larger in ventilation calculation of urban tunnel and the calculation value of air demand is larger than normal. Thinks that the base emission and concentration control value of NOx in motor vehicle exhaust emission should be paid attention to in the formation of relevant standards and engineering design. For multi-ramp tunnels, the pollutant concentration at the tunnel exit near sensitive buildings can be reduced by inducing traffic organization and adjusting the air rate distribution of separated ramp.