S Yudy On The Tunnel Air Temperature Distribution And Its Monitoring In The Metro With Platform Screem Doors System

As an important means of urban transportation,the subway plays a significant role in alleviating the urban traffic pressure because of its small space consumption and large transportation capacity.However,with the metro opened and operated,many cities are exposed to the thermal environment degradation in underground railway tunnels.To ensure that the metro can runs normally,the metro environment control system is required to monitor and control the tunnel temperature,so as to the temperature won’t be higher than the metro design specification.Yet how to establish a reasonable monitoring system to monitor the temperature,especially the highest temperature in tunnels,is an urgent problem that needs to be solved.In consideration of this situation,the metro equipped with Platform Screen Doors(PSDs)is taken as the study object;further study on the tunnel air temperature distribution of the metro with PSDs is deeply discussed in this paper.So that it can provide a theoretical foundation for the establishment of the temperature monitoring system and how to monitor the highest temperature in metro tunnels.Taken the metro with PSDs as the study object and by referring to Chengdu Metro Line 1,the typical metro tunnel model is built in this paper.Combined with this model,the Subway Environment Simulation computer program is used to calculate the air temperature in the underground tunnels.Based on the calculation,the characteristics of the tunnel air temperature and the highest temperature distribution in metro with PSDs is analyzed and summarized.The tunnel air temperature is affected by various factors.In order to analysis the influence of trackway exhaust systems,trains,piston vent shafts,the tunnels between two stations,outdoor environment and passenger flow,the changes of air temperature distribution and the highest temperature location are discussed by simulating the thermal environment in different conditions.According to these tunnel air temperature regularities,the methods to monitor the highest tunnel temperature are raised in this paper.In the end,the thermal environment of Chengdu Metro Line 18 at sunmmer evening-rush-hour is simulated.How the tunnel temperature distributes and where the highest temperature appears in are studied.Based on that,the monitoring program for the tunnel temperature in Chengdu Metro Line 18 is esteblished.Eventually,the results reveal that the tunnel air temperature distributes in a cyclical variation;the value of the highest temperature is mainly affected by the numbers of running trains on the tunnel,the train’s highest running speed and the ttrackway exhaust system;besides,the distrbution location of the highest temperature might be great influenced by the train’s parking place,its acceleration and decelaration in station tunnels.So as to obtain the highest temperature value in the whole metro line tunnel,it suggested that the temperature measuring points should be installed at a range of 12 meters in every station tunnel where the train headstock parks in.In connection with the engineering practice,the monitoring program for the tunnel temperature in Chengdu Metro Line 18 is esteblished.Besides,the placement of measuring points and the selection of the temperature sensor are stated and illustrated.