Optimization of Insulation Layer Thickness and Analysis of Lining Response under Thermal-mechanical Coupling in High Temperature Tunnels
(1. State Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing 400074; 2. School of Civil Engineering in Chongqing Jiaotong University, Chongqing 400074; 3. Power China Guiyang Engineering Corporation, Ltd, Guiyang 550081)
Abstract：
As the main bearing structure, the thermal-mechanical coupling response law of tunnel lining is very im? portant in the study of thermal insulation lining of high temperature tunnels. Focused on the high temperature tunnel and based on the field temperature monitoring and material thermal parameter test data, the ANSYS thermalmechanical coupling analysis model is established around the characteristics of high temperature tunnel thermal insulation lining and the requirements of ventilation and cooling. The characteristics of ventilation and heat transfer in high temperature tunnel construction are revealed, the spray thickness of polyurethane insulation layer is optimized,and the thermal-mechanical coupling response law of secondary lining structure is discussed. It is concluded that the mechanical and thermophysical parameters of thermal conductive media in each layer of thermal insulation lining structure have significant temperature effect. The thermal conductivity of foamed polyurethane material increases nonlinearly with the increase of temperature, while the temperature effect of thermal conductivity of limestone and concrete is opposite. The uniaxial compressive strength and deformation modulus of the three media decreased with the increase of temperature, while the peak strain increased with the increase of temperature. The temperature effect of thermal conductivity, strain hardening characteristics and post-peak load retention of foamed polyurethane were related to the porous structure. In the construction ventilation environment, the temperature of tunnel surrounding rock and the radius of heat regulating ring decrease with time and gradually become stable. Under the action of thermal-mechanical coupling, the sensitive temperature point of the principal stress extreme value of the secondary lining structure and the critical temperature of the deviation of the principal stress extreme position are consistent with the safety threshold (50°C) of the secondary lining structure temperature.
LIU Xingchen1,
2 HUANG Feng1,
2 ZHOU Yang1 etc
.Optimization of Insulation Layer Thickness and Analysis of Lining Response under Thermal-mechanical Coupling in High Temperature Tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(5): 108-117
2022, Vol. 59 