冻融循环对季冻区隧道衬砌混凝土导热系数影响研究

为研究冻融循环作用对衬砌导热系数的改变，将混凝土简化为多孔介质模型，利用Hamilton and Crosser理论计算模型和COMSOL仿真软件对不同孔隙率的混凝土试件导热系数进行计算和分析。研究结果表明： 1）通过对混凝土随机分布模型的有效导热系数进行逆运算，得到不同冻融循环作用下不同孔隙率的混凝土模型的有效导热系数，进而确定混凝土试件有效导热系数与冻融循环次数之间呈非线性函数关系； 2）衬砌导热系数在冻融循环作用下，初期导热系数随着冻融循环次数的增加而下降，中期随着冻融循环次数的逐渐增加，导热系数出现较小程度的增大。

Study on Influence of Freeze thaw Cycles on ThermalConductivity of Tunnel Lining Concrete in Seasonal Freezing Zone

In order to study the effect of freeze thaw cycles on the thermal conductivity of tunnel lining, the concrete is simplified to a porous media model, and the thermal conductivity of concrete specimens with different porosities is calculated and analyzed by Hamilton and Crosser theoretical calculation model and simulation software COMSOL. The research results show that: (1) The inverse calculation is carried out on the effective thermal conductivity of the concrete random distribution model, and the effective thermal conductivity of the concrete model with different porosities under different freeze thaw cycles is obtained, which helps to determine the non linear functional relationship between effective thermal conductivity of the concrete specimens and the freeze thaw cycle. (2) The thermal conductivity of lining concrete decreases first and then increases with the increase of freeze thaw cycle, and finally becomes stable (increases a little).