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

Table 3

Relevant parameters of the Fenghuoshan tunnel.

Related parameters	Parameter value
Heat transfer coefficient of the surrounding rock (m·°C)	1.650
Heat capacity of the surrounding rock (J/m^3·°C)	2465
Heat transfer coefficient of the shotcrete (W/(m·°C))	1.655
Heat capacity of the shotcrete (J/m^3·°C)	1.617 × 10^3
Heat transfer capacity of the thermal insulation (W/(m·°C))	0.003
Heat capacity of the insulation (J/m^3·°C)	0.072 × 10^3
Heat transfer coefficient of the lining (W/(m·°C))	1.825
Heat capacity of the lining (J/m^3·°C)	1.312 × 10^3
Air speed (m/s)	0.3
Air heat transfer coefficient (W/(m·°C))	0.02
Freezing and thawing depth around the surrounding rock (m)	10
Heat transfer coefficient between the air and the surrounding rock (W/(m·°C))	20