عنوان مقاله [English]
Nowadays ventilation of railway tunnels in Iran with regard to their age and the need for increasing the traffic lines, especially for the west part of the country, is of paramount importance. The most important factors affecting ventilation design of these tunnels are heat and the gases produced by fuel combustion in diesel engines. The heat produced by these engines may increase the temperature of the air in tunnels so that locomotive motors are not able to operate with a reasonable efficiency. Products resulting from fuel combustion may also cause problems for the tunnel users. Therefore, ventilation of the tunnels should be designed with respect to these two aspects. The method presented in this paper, which is the first scientific and practical step in this regard, is based on using present railway transportation facilities and approaching standardization of the appropriate required air inside the tunnel. Studyin of different ventilation methods shows that excavation the galleries and connected shafts the air through which may be transferred, or installation of the equipment inside the tunnel are not technically and economically desirable due to lack of geotechnical surveys and therefore knowledge about the earth materials, elongation of the proposed galleries and shafts and finally lack of the clearance in tunnel. These considerations resulted in choosing the method of installing a powerful jetfan outside the tunnel and using the air-tight gates, one of the advantages of which is prevention of interference between the maintenance procedures with the train movement.In this paper the requirement for installation of ventilation facilities in the railway tunnels in Lorestan province in the west of Iran, with particular emphasis on the 102 Lorestan Railway Tunnel has been discussed. First of all the possibility of applying the different methods of ventilation in this tunnel was studied and according to the geometric conditions of the tunnel and topographical situation of the area, the possibility of using the hand dollies and access tunnels was disregarded. The transverse and semi transverse ventilation systems was not preferred either, due to the complexity of these systems compared to longitudinal ventilation systems.Finally application of strong fans with 130m3/s and the 3 KPa pressure and an engine with 600 KW power along with utilization of ventilation gallery with 50 m length and angle towards the main tunnel and airtight doors, has been selected as the optimal ventilation systems for this tunnel.