Complementary ventilation operational test in large longitudinal slope double-hole tunnel

In order to solve the technical problem that whether ventilation shafts are needed to set up or not in upstream tunnel when the air inflow and outflow are imbalanced in the large longitudinal slope double-hole tunnel,Dabie Mountain Highway Tunnel was selected as an entity engineering for analysis.The CO concentration,visibility index,and air velocity in the complementary network ventilation tunnel were tested on site,and the effect and existing problem of ventilation channel in the double-hole complimentary network ventilation system were analyzed.Test result indicates that the complimentary network ventilation can meet the control criteria of contaminant concentration.Two ventilation channels can play the role of airflow bi-direction exchange,and the exchanged air volume can meet design requirement,therefore,the complementary ventilation plan is feasible.When ventilation loads in upstream and downstream tunnels are imbalanced,the complementary ventilation can be used instead of ventilation shaft in upstream tunnel for large longitudinal slope extra-long tunnel.4tabs,7figs,16 refs.