Energy Saving Construction Ventilation Effect by Using Natural Wind of Shaft in Super-Long Highway Tunnel

In order to solve the problem of how to make effective use of the natural ventilation in the shaft to assist the mechanical ventilation in the long tunnel and improve ventilation effect and save energy consumption, based on the construction ventilation of Guantian tunnel, the influence parameters of natural ventilation in shaft were carried out by theoretical analysis, numerical simulation and field test. The research results show that the natural ventilation of shaft has a certain effect on assisting mechanical ventilation under specific temperature conditions, the effect of strengthening the ventilation by changing the diameter of the shaft is limited. Within 250m of shaft depth, the ventilation effect of the shaft increases with the increase of the shaft depth, but the ventilation effect has no significant change with the depth increasing when the shaft depth is more than 250m. The greater the temperature difference, the better the natural ventilation effect of the shaft, and the natural ventilation effect of the shaft as outlet in winter is better than that of the shaft as inlet in summer. The introduction of fresh airflow into the main tunnel is the key to the implementation of the air intake scheme of the shaft. It is reasonable to set the fan away from the 5m position of the middle line of the shaft.