Experimental Study On The Environment Of Subway Tunnels And Stations In The Severe Cold Area

The Harbin Metro,which is located in the cold region,faces outdoor temperatures of-20 to-30℃ in winter.Due to the existence of the piston effect,the public area environment in the subway station in winter and the environment in the tunnel are facing great challenges.In this article,I conduct a long-term actual measurement experiment of temperature and humidity,wall temperature and carbon dioxide concentration in the tunnels and public areas of the stations of Harbin Metro Line 1 and Line 3 for a year,and a short-term actual measurement experiment of questionnaire survey and wind speed survey in the coldest month.Then,I obtain the corresponding data and analyze it.These data will provide the basis for the subsequent cold protection measures and wind system transformation in the Harbin subway station,and also provide data reference for the subway lines to be built in the severe cold areas,and improve the design of the cold protection and ventilation in the station.This article first introduces the details of the long-term actual measurement experiment and short-term actual measurement experiment.The actual measurement experiments are conducted at the entrance and exit sections of Harbin Subway,Heilongjiang University Station and its two end sections of Harbin Subway Line 1,and Haxi Street Station and its two end sections of Harbin Subway Line 3.The long-term actual measurement experiment mainly obtains the temperature and humidity,the wall surface temperature and the carbon dioxide concentration in the tunnel and the station,and I will analyze the whole year.The questionnaire survey part of the short-term actual measurement experiment is to obtain passengers’ subjective opinions on the environment inside the station,and the wind speed data is to test the effectiveness of various cold-proof measures in the subway.Through the measured data,the following three aspects of research are conducted.First,through the long-term air temperature data and wall temperature data in the tunnel and the public area of the station,the current heat accumulation phenomenon in Harbin subway is analyzed.The data proves that the heat storage in the soil of Heilongjiang University Station on Line 1 tends to be saturated,and the Haxi Street Station on Line 3 is in the initial state of heat storage.And put forward measures to deal with heat accumulation in stages,give full play to the advantage of heat accumulation which can increase the temperature in the winter station.Second,using the questionnaire survey data to obtain passengers’ feelings about the environment of the two subway stations,the temperature of Heilongjiang University Station has an advantage,the air quality of Hasi Street Station is dominant,and the feeling of blowing at the entrance and exit is the same.At the same time,the thermal comfort analysis is carried out using the site environmental data obtained from the actual measurement,and it is concluded that there are some deficiencies in the PMVPPD indicator,RWI indicator and HDR indicator.Subsequently,a new thermal comfort index dominated by temperature is proposed,and the calculation results of the new index are verified using the questionnaire data,the error at both stations was about 10%,and it is practical.Third,using the relationship between the concentration of carbon dioxide and the amount of fresh air here,the calculation of the amount of fresh air ventilation in the inlet and outlet and the piston air duct is performed separately.Through the verification of the measured wind speed data,it is found that the calculation result error at the entrance and exit is small,which is practical,the result error of the piston air duct is large,and more experimental data is needed to support it.At the same time,the shortterm wind speed data is used to analyze the effectiveness of individual cold-proof measures at the entrance and exit and the piston air duct,and based on the analysis results,the improvement plan of insulation measures was proposed.Renovation plan is also proposed for the mechanical wind system in the station,retaining heat recovery while adjusting the return air position,to minimize the infiltration of cold outdoor air in winter due to the piston effect.