REDUCTION OF HUMIDITY IN TUNNELS OF KIEV METROPOLITEN, BY CHANGING THE OPERATION MODES OF VENTILATION INSTALLATIONS

Abstract

The implementation of the operation modes of the ventilation system in accordance with the current schedules of the service interconnect lines (SIL) of the Kiev Metro consists of forcing air into the tunnels from the stations in the summer period.The humidity of the tunnel air of the SIL between the Klovska-Maydan Nezalezhnosti-Khreshchatyk metro stations from April to October from 2005 to 2018 exceeds the permissible value of 75 % and sometimes reaches 100 % (fog).The high humidity of the tunnel air significantly accelerates the processes of destruction of the rim walls of the tunnels and the corrosion of expensive equipment of the power supply system, which can cause a short circuit of the SIL electrical equipment and stop the movement of trains in the nearest worker lines.The main reason for the high humidity of SIL tunnels in the summer period, as evidenced by the experimental data, is that the tunnel air from metro stations has higher an average absolute humidity at 2 g/kg compared to the air that is delivered from the ventilation tunnels in the SIL tunnels. Therefore, to reduce the relative humidity of the SIL tunnels air, has been proposed to delivery air from the environment into the tunnels, and not from the metro stations.The analysis of the change in the average monthly value of the relative air humidity from April to August during the delivery of air from the environment into the tunnels has been carried out and it has been established that the relative humidity of the SIL tunnels air will not exceed the permissible value of 75 %.In the existing schedules of the operation modes tunnel ventilation of SIL tunnels of the Kyiv Metro during the summer period recommended changing the operating modes of the ventilation units so that ambient air is forced into the SZG tunnels by ventilation units 115 and 229, and air from the tunnels is carried out by station fans. Approbation of the recommended operation modes of the ventilation systems was carried out, which led to a decrease in the humidity of the tunnel air in the range from 50 to 75 %.