Study On Operating Ventilation Of Extra-long Tunnel On A Single Heavy Haul Railway With Diesel Locomotive Traction In Africa

The operating ventilation of extra-long tunnel on the single heavy haul railway with diesel locomotive traction often have many problems,such as needed ventilation in both directions,large air flow volume,high energy consumption,et al.Needed to choose a ventilation scheme,which can meet both the requirements and the economy is better,for the tunnel during the engineering design.At present,there is no practical engineering experience can learn from,and the relevant research data is less.In order to provide a valuable reference for engineering design,this paper uses the numerical simulation method to study the operating ventilation of Dongmamu Tunnel in Africa.The main contents and conclusions are as follows:First,a calculation model of the full-jet ventilation of extra-long tunnel is established to simulate the effect of normal ventilation and advanced ventilation under different conditions.And the influence of the relevant parameters on the advance ventilation is analyzed.The results show that:(1)Under the current design conditions,the normal ventilation can not meet the ventilation requirements of heavy duty and no-load conditions.Although the advance ventilation can meet the ventilation requirements of heavy-duty conditions,can not meet the other;so the tunnel with a full-jet ventilation program is not feasible.(2)If the calculation conditions are changed,such as the tunnel clearance is less than 34m2,the speed of the no-load train is less than 80 km/h or the length of the no-load train is more than 3000m,the advance ventilation can meet the ventilation requirements of the no-load condition.Then,the calculation model of the sections longitudinal ventilation with a inclined shaft is established,and the scheme of the ventilation system is discussed.The effect of different ventilation modes under different working conditions is simulated,and the influence of the relevant parameters on the advance blowing ventilation is analyzed.The results show that:(1)Under the current design conditions,the normal exhaust ventilation and the normal forced ventilation cannot meet the ventilation requirements of heavy duty and no-load conditions.The advance forced ventilation can meet the heavy load conditions but cannot meet the other.So,the ventilation program with the inclined shaft of construction is not feasible.(2)If the conditions are changed,such as the inclined shaft of construction is located in the range of 7500?8200m or the speed of the no-load train is less than 70 km/h,the advance forced ventilation can meet the ventilation requirement of the no-load condition.It is feasible that the operating ventilation uses an inclined shaft of construction.Finally,according to the characteristics of the tunnel's ventilation,the exhaust ventilation scheme with the one of two inclined shafts is put forward,the effect of ventilation under different working conditions is simulated,the position of the inclined shaft is determined and the impact of the relevant parameters on the exhaust volume is analyzed.The results show that:(1)When the inclined shaft is in the proper position,the ventilation scheme can meet the ventilation requirements of each condition,and this scheme is feasible.(2)The optimal position of the 1#inclined shaft is at 4800 m from the tunnel inlet,and the optimal position of the 2#inclined shaft is at 4100 m from the tunnel outlet.The required exhaust volume is least when the inclined shaft is in the optimal position.(3)Considering all aspects,this ventilation scheme is more reasonable than others for Dongmamu Tunnel.