Application of the twin-tube complementary ventilation system in large-slopping road tunnels in China

Abstract

To solve the imbalanced problem of wind pressure between left tunnel and right tunnel in the large-slopping tunnel, the complementary ventilation system is proposed, and the design theory and calculation method are also discussed. Results from a experiment carried out in a model tunnel (1:10) with complementary ventilation are presented and applied to the Dabieshan tunnel. It is found that the twin-tube complementary ventilation system can bridge two tunnels and exchange air between tunnels to ensure adequate air quality. The fresh air in the downhill tunnel can be transfer into the uphill tunnel to dilute air in the uphill tunnel. Field measurements were performed in the Dabieshan tunnel on wind speed, CO concentration, and VI (visibility index) concentration. Measurement results also indicate that the twin-tube complementary ventilation system can meet the ventilation requirements for tunnels. Compared with traditional ventilation systems, the complementary ventilation can be used to ensure adequate air quality in tunnels by eliminating the ventilation shaft in uphill tunnel and saving initial investments and operation costs.