DESIGN METHOD FOR SUPPORT STRUCTURE OF ROAD TONNEL IN COLD REGION CONSIDERING THE DECRESE IN COST OF CONSTRUCTION

隧道衬砌的设计和施工主要依据以往的经验。考虑衬砌的力学特性，结合严寒地区抗冻法隧道的发展，合理选择结构，降低施工成本。本研究的主要结果总结如下：1。新约束曲线的提出：本研究提出了新的支撑约束曲线（即支撑刚度）。为此，隧道被理想化为一个完美的圆柱形薄壳，两端有两个加强钢环。主要结果如下：(1)本研究得到的支座刚度结果小于薄环理论得到的结果；最大误差为20%。(2)加劲钢环的作用可以用有效宽度（0.35 ~ 1）L来表示，其中L为两个环之间的长度。寒冷地区隧道总长度温度的估算：对于寒冷地区公路隧道的隔热设计，有必要估算和/或确定隧道总长度的最低（周期）温度。通过理论分析，提出了考虑隧道地面与空气对流/传导的温度估算公式。本研究得到以下结果：(1)计算值与观测值吻合较好。(2)从隧道入口开始合理确定必要的防冻处理长度。

Tunnel lining is designed and constructed mainly based on the past experience. Considering mechanical characteristic to lining and the development of anti-frost method tunnels in cold region lead to a proper structure, and it can reduce the cost of construction. The principal results of this study are summarized as follows :1.Proposal of newly confinement curve : In this study, the newly confinement curve for support (namely stiffness of support) is developed. To this end, the tunnel is idealized as a perfectly cylindrical thin shell with two stiffening steel rings at ends. The mainly results are as follows:(1)The results for the stiffness of support obtained by this study are less than the ones obtained by the thin ring theory; the maximum error is 20 percent.(2)The effect of stiffening steel ring may be presented in terms of an effective width (0.35〜1)L where L is the length between two rings.2.Estimation of temperature overall the length at tunnels in cold region : For heat insulator design at road tunnel in cold region, it is necessary to estimate and/or determine the lowest (periodical) temperatures overall the length at tunnel. An equation for estimating temperature by a theoretical analysis considering heat convection/conduction between the tunnel-ground and the air flow is presented. From this study, the following results are obtained;(1)The calculated values well agree with the observed ones.(2)We can reasonably determine the necessary length of anti-frost treatment from tunnel entrance.