A DESIGN METHOD OF ROAD TUNNELS IN COLD REGION

隧道内冰柱和边墙结冰成为隧道运输和维护的难题。近年来，在既有隧道中研制了一种用于衬砌表面防冰的隔热材料。本研究的目的是提出一种简化的绝热层设计方法，主要内容如下：（1）提出了一个简单实用的绝热层厚度估算公式。该方程是通过使用一维隧道-地面模型和非稳态周期性热分析得到的。与其他解的比较表明，所提出的方程提供了令人满意的精度。利用该方程可以合理地确定绝热材料的最佳材料和最佳厚度。此外，该方程有助于更好地理解隧道-地面系统的热特性。(2)In为了识别出现在所提出的方程中的未知热参数（热导率和热容），将扩展卡尔曼滤波器与一维有限元热分析相结合。通过与现场实测数据的比较表明，该方法具有较高的精度。(3)In为了估计公路隧道规划位置处的未知温度，在随机方法的基础上，采用了半方差图法。将估算温度与实测温度进行了比较，结果令人满意。

Icicles and side wall ices in tunnels became a problem for transportation and maintenance. Recently a heat insulator for icicle prevention at the lining surface has been developed in the existing tunnels. The purpose of this study is to propose a simplified design procedure for heat insulator.This project is summarized as follows :(l) A simple practical equation for estimating the thickness of heat insulator is presented. The equation is obtained by using a one-dimensional tunnel-ground model and a non-steady periodic thermal analysis. A comparison with other solutions suggests that the proposed equation provide satisfactory accuracy. By using the equation presented, we can reasonably determine the optimum material of heat insulator and its optimum thickness. In addition, the equation is useful for a better understanding for the thermal characteristics of the tunnel-ground system.(2)In order to identify unknown thermal parameters (thermal conductivity and heat capacity in ground) in appearing the proposed equation, the extended Kalman filter in combination with the one-dimensional finite element thermal analysis is used. A comparison of the temperatures calculated from identified parameters with the measured fild data shows that the method is sufficiently accurate for practical purposes.(3)In order to estimate the unknown temperatures at a planning site of road tunnels, Semi-Yariogram is used on the basis of the a stochastic method. A comparison of the estimated temperatures with the measured fild data gives satisfactory results.