Abstract: To clarify the air volume and pollutant distribution of each ramp and main line of underground interchange in complex urban areas, and determine the operating condition of the exhaust fan and the configuration of the jet fan in the working shaft under the operation ventilation mode, the network ventilation algorithmbased IDA RTV software is used to simulate and calculate the distribution of pollutants and air volume in the tunnel under different traffic conditions. The fan configuration under different traffic conditions is determined. Meanwhile, the proportion of pollutant discharge in the shaft under different combined conditions is simulated and the optimal combined conditions are determined. The results show that: (1) when the national Ⅳ standard is used to calculate the pollutant emission of vehicles, the traffic wind can meet the requirements of the tunnel air volume under the current traffic volume and the operating conditions without jet fan; (2) a certain number of jet fans need to be opened under blocking conditions. In the case of wind exhaust of the southern route, it is recommended to adopt the mode of one air supply fan and three air exhausters.  In this case, the pollutant discharge ratio of the vertical shaft is 65%.

Key words: highway tunnel, operating ventilation, numerical calculation, underground interchange, network ventilation