延崇高速公路金家庄特长螺旋隧道温度场分布规律及保温层研究

为揭示寒区螺旋隧道温度场时空分布规律，依托金家庄特长螺旋隧道，采用现场监测方法研究寒区螺旋隧道温度场变化规律。基于此，通过数值模拟建立三维模型探究进口风速风温对温度场的影响，并拟合结果数据获得保温层敷设长度计算公式。研究表明： 1）随着进洞深度的增加，进、出口洞壁处空气年平均温度上升，而年温度振幅减小； 出口年温度振幅变化幅度略小于进口。2）隧道贯通后，洞内温度受两侧洞外相对低温的共同作用，同一断面处年平均温度下降，年温度振幅增大。3）隧道在直线段温度场分布规律与同条件的直线隧道一致，从曲线段开始内外径温度曲线发生分叉，外径侧温度较直线隧道温度大；而内径侧温度反之。4）进口风速越大、风温越低，对隧道温度场越不利，通过拟合公式，金家庄特长螺旋隧道进口的保温层长度至少需要1 239 m。

Study of Temperature Field Distribution Laws and Thermal Insulation Layer of Jinjiazhuang Extra Long Spiral Tunnel on Yanqing Chongli Highway

To reveal the temporal and spatial distribution laws of temperature in cold region tunnels, based on the Jinjiazhuang extra long spiral tunnel, the field monitoring method is employed to investigate the variation laws of temperature of the spiral tunnel in cold regions. Furthermore, a three dimensional model is established using numerical simulation to investigate the influence of inlet wind speed and temperature on the temperature field, and the formula of the insulation layer laying length is obtained by fitting the simulation results. The research results reveal the following: (1) The annual average temperature of air at the inlet and outlet of the Jinjiazhuang spiral tunnel increases as the depth into the tunnel increases. However, the annual temperature amplitude decreases gradually, and the annual temperature amplitude at the inlet of the tunnel varies more than that at the outlet. (2) After tunnel penetration, the annual average temperature and temperature amplitude of the same monitoring section decreases and increases, respectively, under the joint action of the relative low temperature outside the tunnel on both sides. (3) The temperature field distribution laws of the tunnel in the straight section are the same as that of the straight tunnel under the same conditions, and the temperature curves of the inner and outer diameters bifurcate from the curved section, i.e., the temperature of the outer diameter side is higher than that of the straight tunnel, while the temperature of the inner diameter side is reversed. (4) The larger the inlet wind speed and lower the inlet wind temperature, more unfavorable the tunnel temperature field. According to the fitting formula, the length of the insulation layer at the inlet of the Jinjiazhuang extra long spiral tunnel should be at least 1 239 m.