项目名称： 基于多频次短周期冻融循环的寒区隧道防冻理论与应用

项目编号： No.51478473

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 伍毅敏

作者单位： 中南大学

项目金额： 80万元

中文摘要： 随着我国高寒地区各类隧道特别是高铁隧道大量投入营运，破解寒区隧道冻害形成机理的需求日益紧迫。申请者前期对实际隧道衬砌温度的长期连续实测表明寒区隧道每年可能经历数十至上百次短周期正负温交替，可为寒区隧道冻害机理研究提供新思路。本项目将立足多区域多类型寒区隧道开展衬砌温度连续实测工作，分析隧道衬砌温度短周期波动的振幅、周期特征及其关键影响因素，探索建立其量化模型。在此基础上，在室内模拟气温的短周期正负波动，对自然服役状态中衬砌混凝土与隧道结构的冻融损伤过程进行模拟研究，揭示多频次短周期不充分冻融对非饱和混凝土材料性能劣化的影响机制，以及复合防水层普遍淤塞积水、隧道结构外侧围岩富水的反复冻胀对隧道结构造成累积损伤效应，提出引起材料或结构损伤的有效冻融循环判据。根据上述冻害产生机制，提出基于有效冻融循环次数、依赖气温波动特征的寒区隧道设防标准和方法，研究抑制和减少衬砌有效冻融循环次数的防冻措施。

中文关键词： 寒区隧道；冻害机理；冻融循环；材料劣化；结构损伤

英文摘要： With the put into operation of a large number of tunnels in cold region of China, especially the operation of lots of high-speed railway tunnels, increasingly urgent demand has occurred to solve the mechanism of frost damage of tunnel. According long-term continuous site monitoring, tunnel structure in cold region may undergo tens to hundreds times of short freeze-thaw cycles in one year, which provide a new ideas for study the mechanism of frost damage of tunnel. Based on long-term continuous site monitoring of temperature in different kinds of tunnels in more regions, this project will study the characters and influential factors of the short-term fluctuations of temperature, and establish its quantitative models. Materials tests of natural unsaturated concrete and model tests of tunnel structure will be carried out to research the effect of these numerous short-period freeze-thaw cycles. Thorough researches will concentrate on the performance degradation of the unsaturated concrete considered with the numerous inadequate frost-thaw processes, and the additive effects caused by the repeated frost heaving of interlayer water between the initial and secondary lining, as well as the tunnel structure and surrounding rock. Criterion of effective freeze-thaw cycles will be developed to identify those may cause material or structural damage. According to the generation mechanism of frost damage, the standard and methods to prevent frost damage will be built based on the times of effective freeze-thaw cycles or fluctuation characteristics of air temperature, and new measures will be developed to decrease the effective freeze-thaw cycles.

英文关键词： Tunnel in cold region;mechanics of frost damage;freeze-thaw cycle;material degradation of concrete;structure damage of tunnel