基 于 材料 热 参 数 试 验的 负 温 隧 道温 度 场 分 析

In view of the temperature field problem of Asia’s first four-season cross-country skiing tunnel reconstructed from an existing tunnel, based on the study of the thermal conductivity of tunnel materials by the HOTDISK method, steady-state heat transfer models under different protection conditions were established by using the finite element method and the multi-layer cylinder heat transfer theory, respectively. The temperature field distribution characteristics of the negative temperature tunnel were analyzed, and the influence laws and sensitivities of various factors were investigated. The results show that the freezing of the tunnel affects the material properties of the tunnel structure; the thermal conductivities of the saturated rock sample and concrete in the frozen state are 8%-20% higher than those in the thawed state; the thermal resistance under the protected condition increases by nearly 9 times compared with that under the unprotected condition, and the heat flow decreases to 1/10; the thermal resistance component of each material layer is inversely proportional to its thermal conductivity and increases approximately logarithmically with the thickness of the insulation layer; the tunnel temperature field has an approximate logarithmic relationship with the thermal conductivity of the surrounding rock and the thickness of the air layer and has a low correlation with the thermal conductivity of the lining; as the thermal conductivity of the insulation material increases, the insulation effect decreases rapidly. The main factors affecting the distribution of the tunnel temperature field are the thickness of the insulation layer, the thermal conductivity of the insulation layer, and the thermal conductivity of the surrounding rock. Intervals can be set in the air layer to reduce the impact of convective heat transfer, and active heating technology can be applied in the lining to prevent the freezing of the tunnel structure.