Optimal design of thermal insulation layer of a tunnel in permafrost regions based on coupled heat-water simulation

Li, Shuangyang; Niu, Fujun; Lai, Yuanming; Pei, Wansheng; Wang, Yu

doi:10.1016/j.applthermaleng.2016.09.033

Cited by 92 publications

(30 citation statements)

References 20 publications

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“…Yan examined the effects of variations in mechanical ventilation speed and different cold regions on the design of the thermal insulation layer on the basis of the numerical mode l [25,26]. Li emphasized the effects of soil temperature and moisture content around the tunnel on the optimal thickness of the tunnel insulation layer [27][28][29]. e thermal insulation performance index of a thermal insulation material is mainly determined by thermal conductivity [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

Sun

Zhuang

et al. 2020

Advances in Materials Science and Engineering

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This study investigates the distribution of pore water on the basis of the measured mass moisture content after soaking the tunnel insulation material. This study also analyzes the influence of the distribution of pore water on the thermal conductivity of the material on the basis of this mass moisture content. Scanning images of phenolic and polyurethane insulation boards are obtained by computer tomography (CT). The gray volume moisture content (Gv) is deduced based on the CT scanning images, to determine the distribution of pore water (Gv is the ratio of the volume of the water sample (represented by the gray value) to the volume of the saturated water sample (represented by the gray value) which is the gray volume moisture content of the sample). The correlation between gray volume moisture content and mass moisture content is determined by comparing different algorithms of gray volume moisture content and volume moisture content. The relationship between mass moisture content and thermal conductivity can be determined using a self-made quasi-steady-state tester, whereas the relationship between gray volume moisture content and thermal conductivity can be derived indirectly. Related experimental research can predict the thermal conductivity of thermal insulation materials by using a new perspective and shows the influence of pore water distribution on the thermal conductivity of materials.

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Section: Introductionmentioning

confidence: 99%

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

Sun

Zhuang

et al. 2020

Advances in Materials Science and Engineering

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“…e temperature monitoring results in the permafrost tunnel indicate that the lining structure within a certain distance from the tunnel opening was more prone to freeze damage under a freeze-thaw cycle than the other sections of the tunnel [2,5,8,9,11,15,16]. us, it is necessary to strengthen the lining structure and the antifreeze measures within a certain distance from the tunnel opening [7,15,[17][18][19]. ese areas can be optimized with an investment.…”

Section: Introductionmentioning

confidence: 99%

A Closed‐Form Solution for the Analysis of Antifreeze Disease Fortification Length in a Permafrost Tunnel

Zhang

et al. 2020

Advances in Civil Engineering

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Frost damage in permafrost tunnels is very common, and this can have a negative influence on traffic. The most serious frost damage typically occurs at a certain length from the tunnel opening. Thus the antifreeze measures of the lining structure in this area need to be strengthened. In this study, the antifreeze disease fortification length for permafrost tunnels is determined from heat transfer and mathematical physics equations by the theoretical analysis method. The temperature distribution characteristics of the lining along the tunnel axis under the influence of the tunnel depth, the tunnel radius, the wind velocity at the tunnel opening, and the thermal conductivity of the insulation layer are analysed. The results show that the longitudinal temperature characteristics in the tunnel axis are influenced by many factors. The proposed antifreeze disease length of the permafrost tunnel was found to be approximately 31 times of the tunnel diameter, which agrees with the results of the numerical simulation. It verifies the rationality of the theoretical calculation. This value, 31 times of the tunnel diameter, can be used as a reference for the design of the tunnel antifreeze disease fortification length.

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“…e results show that the thermal insulation layers with thicknesses of 5 cm and 7 cm can increase 4.85°C and 5.8°C temperature, respectively, to prevent the Houanshan tunnel frost. Li et al established a coupled heat-water model to calculate the optimal thickness of the thermal insulation layer with a thermal conductivity of 0.025 W/(m·k) for the Jiangluling tunnel in China [24]. e lowest ambient air temperature outside the tunnel is lower than − 15°C.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Insulation Effect of Thermal Insulation Layer in the Seasonally Frozen Region Tunnel: A Case Study in the Zuomutai Tunnel, China

Zhao

Chen

Luo

et al. 2019

Advances in Civil Engineering

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In this study, a field temperature test was performed to reveal the insulation effect of the thermal insulation layer installed at lining surface. The thermal insulation layer is made of polyphenolic, and the thickness is 7 cm. According to the test results, the temperature of the thermal insulation layer and lining continuously changes with the air temperature in the tunnel in an approximately trigonometric function. The temperature of tunnel lining without thermal insulation layer is close to the air temperature, which results in the lining frost in winter. The maximum temperature difference between the two sides of the thermal insulation layer can be 27°C. In the section whose buried depth is more than 11.4 m, the temperature of lining with thermal insulation layer in winter is mainly influenced by the cold air in the tunnel. When the monthly mean and lowest daily mean air temperature are lower than −10°C and −14.3°C in the coldest month, the temperature at the inner side of the thermal insulation layer is below 0°C. When the buried depth is less than 11.4 m, the temperature of lining is also influenced by the low temperature at ground surface. The temperature of lining is lower. The thicker thermal insulation layer and even active heat measure are needed. Therefore, the design of thermal insulation layer thickness should consider the air temperature distribution and tunnel buried depth along the tunnel length.

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Optimal design of thermal insulation layer of a tunnel in permafrost regions based on coupled heat-water simulation

Cited by 92 publications

References 20 publications

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

Thermal Conductivity Characteristics of Thermal Insulation Materials Immersed in Water for Cold‐Region Tunnels

A Closed‐Form Solution for the Analysis of Antifreeze Disease Fortification Length in a Permafrost Tunnel

Investigation of the Insulation Effect of Thermal Insulation Layer in the Seasonally Frozen Region Tunnel: A Case Study in the Zuomutai Tunnel, China

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