Abstract:

To address the health hazards posed to construction workers by the high temperature and humidity at a high geothermal tunnel construction site and mitigate the risks during construction, real-time continuous monitoring is conducted on the air dry-bulb temperature, air relative humidity, wet-bulb globe temperature(WBGT) index, and the upper arm skin temperature and heart rate of 20 construction workers engaged in moderate intensity labor in a specific high geothermal tunnel in China. Based on measured data and mathematical modeling, the humid and hot environment in the high geothermal tunnel is categorized into low risk, relatively low risk, medium risk, relatively high risk, and high risk. The threshold values for environmental parameters at each level are determined. The results indicate the following: (1) In the construction environment of the high geothermal tunnel, the threshold values for low-risk conditions are 26 ℃ for air dry-bulb temperature, 30% for air relative humidity, and 20 ℃ for the WBGT index. The threshold values for medium risk are 37 ℃, 64%, and 32  ℃, respectively, whereas for high risk, they are 43 ℃, 81%, and 40 ℃, respectively. (2) Further calculations yield the threshold values for the discomfort, heat, and corresponding change indices at the medium risk level at 25.42 ℃, 26.31 ℃, and 0.28 ℃, respectively. At the high-risk level, the threshold values are 28.59 ℃, 35.30 ℃, and 0.38 ℃, respectively.

Key words: high geothermal tunnel, environmental parameters, physiological parameters, mathematical programming, humidity and heat environment classification