Effects Of Thermal,Acoustic Environments On Workers’ Psychological And Physiological Stress In Deep Underground Spaces

The construction and exploitation of subterranean space are becoming increasingly important as cities keep on expanding.In China,the lack of national-level coordination arrangements in the early stage has led to the depletion of shallow underground space in some developed areas.The international community has developed and utilized underground space earlier than China,and the current direction of development internationally is stereoscopic.All signs indicate that the development of deep underground spaces is urgent.However,due to their unique environmental characteristics(high temperature,occupational noise,etc.),deep underground spaces considerably impact workers’ physiological and psychological health.At present,there are relatively few studies on the physiological and psychological health and safety of personnel in deep underground spaces,so it is indispensable to investigate the influence of environmental factors on the physiological and psychological stress of workers in deep underground spaces to ensure the health and safety of workers in the development process.For these reasons,this study aims to investigate the effects of thermal and acoustic environments on workers’ psychological and physiological stress in deep underground spaces.Based on the disciplines of physiology,psychology,and medicine,this study conducted an experimental study in a climate chamber to simulate the deep underground space work environment using subjective subject experiments and objective measurements.The walls around the climate chamber were covered with rock-like wallpaper to simulate the deep underground working environment.Sixteen adult male subjects were recruited and exposed to two temperatures(30℃,34℃),two humidity levels(65%,85%),and three acoustic pressure levels(55 d BA,70 d BA,85 d BA).The subjects’ thermal sensation,thermal comfort,thermal acceptability,sweat,and mood changes were investigated by subjective questionnaires,and changes in skin temperature,HRV,and blood oxygen saturation were investigated by objective measurements.The subjects’ cognitive abilities were also tested using an online platform.The primary study contents and conclusions are as follows:The effects of three factors,high temperature,high relative humidity,and noise were investigated on workers’ physiological and psychological stresses individually and interactively in deep underground spaces.In the deep underground space environment,temperature and relative humidity had the most significant effect on workers’ thermal response(p < 0.05),and short-term noise exposure did not have a very significant effect on workers(p > 0.05).In the high-temperature background,the acoustic pressure level of noise would have some effect on workers’ thermal response;and in the high-noise background,the effect of temperature on LF/HF(low frequency/high frequency)was more significant(p < 0.05);the effect of the interaction between relative humidity and noise was not very significant.Overall,the interaction is greater than the effect of individual factors,especially the combination of temperature and relative humidity.Secondly,this study also explored the effects of environmental factors on workers’ emotions in deep underground spaces.The results showed that workers’ negative emotions were more incredible in deep underground spaces,sympathetic nerves were always excited,and thermal environmental factors influenced personnel’s emotional changes through the effect on their thermal sensation.The noise pressure level is positively correlated with the psychological stress of workers.Finally,based on the above research findings combined with the existing design indexes for surface and shallow ground spaces,this paper gives design indexes that apply to the deep underground space working environment.