多年冻土区宽幅路基耦合换热机理及边界尺度热效应研究

The coupled heat transfer processes and upper temperature boundary conditions are not only the foundations for the wide permafrost subgrade heat budget quantitative research, but also the first key issues of technical pre-research for the highway in the permafrost regions. This project will carry out the research of the earth-atmosphere coupled heat transfer mechanisms and the thermal boundary scale effects for the wide subgrade in permafrost regions, to build the statistical model of the key influence factors and master the analytical and measuring method of some special influence factors through the significance analysis of the influence factors in coupled earth-atmosphere heat transfer process, to reveal the mechanisms of the unsteady heat transfer inside the earth-atmosphere coupled system through the data interpretation and analysis for the monitoring subgrade sections, the freeze-thawing model experiment, and multi-case numerical simulations, and to propose engineering convenient fitting formula of upper boundary temperature conditions through orthogonal analysis of the upper boundary condition influenced factors and modification of the existing Adherent Layer theory. The project is of a great academic value and engineering significance to reveal the heat transfer mechanisms and thermal boundary scale effects of the wide permafrost subgrade under multi-physical process and spatial-temporal nonlinear variation conditions, to provide scientific and technological support for the design and maintenance of the future permafrost highway engineering.

宽幅冻土路基耦合换热过程与温度上边界条件是量化研究冻土路基热收支的基础性问题，也是多年冻土地区进行高速公路建设前期预研必须首先考量的关键问题。项目拟围绕多年冻土区宽幅路基耦合换热机理及边界尺度热效应开展相关研究，通过宽幅冻土路基耦合换热过程关键影响因素的显著性分析研究，建立和掌握各主要影响因素的统计模型以及部分特殊影响因素的分析与量测方法；通过路基监测断面数据整理分析、冻融循环模型试验及多工况条件下路基传热数值模拟研究，揭示宽幅冻土路基在地气耦合作用下的非稳态换热机理；通过宽幅冻土路基温度上边界条件影响因素的正交分析及对现有附面层理论的分析与改进研究，提出便于工程化应用的宽幅冻土路基温度上边界条件拟合公式。本课题研究成果有助于揭示多物理过程影响、时空非线性变化条件下宽幅冻土路基换热机理与尺度热效应影响规律，进而为多年冻土区高速公路工程的设计与养护提供科技支撑，具有重要的学术价值和工程意义。