季冻区高速铁路路基冻融变形特征研究

为研究季冻区高速铁路路基冻融病害及其变形特征，以兰新高速铁路K1934+190无砟轨道路基断面作为研究对象，在已有的水分迁移控制微分方程、瞬态温度场控制微分方程及土体单元应力-应变方程的基础之上，建立了无砟轨道路基受水分、温度及应力影响的数学计算模型，通过模拟和现场监测对比分析了自2019年10月初至2020年5月初路基的动态变化规律。结果表明，由于水分场、温度场对季冻区高速铁路路基的耦合作用，致使路基水分变化、温度变化及由此产生的温度场重分布、水分场重分布是导致路基发生冻胀融沉的关键因素，其变形在时间域上呈规律性变化，这一结论可为研究冻土地区高速铁路路基冻害治理提供参考。

Research on Freeze-Thaw Deformation Characteristics of High-speed Railway Subgrade in Seasonal Frozen Area

To study the freezing and thawing diseases and deformation characteristics of the high-speed railway subgrade in the seasonal freezing area, the K1934+190 ballastless track subgrade section of the Lanxin high-speed railway is used as the research object. With the existing governing differential equations of water transfer and transient temperature field, as well as the stress-strain equation of soil elements, a mathematical calculation model for the coupled field of the ballastless track subgrade is proposed to compare and analyze the dynamic changes of the subgrade from the beginning of October 2019 to the beginning of May 2020 through simulating and monitoring on site. The results indicate that the variation of moisture and temperature of subgrade caused by the coupling effect of moisture field and temperature field on high-speed railway subgrade in seasonal freezing regions, and the resultant redistribution of temperature field and water field are main reasons for frost heaving and thawing settlement of the subgrade. And it can be concluded that the deformation changes regularly in time domain. This conclusion is expected to provide guidance and reference for further studies on frozen damage control of the high-speed railway subgrade in the frozen soil area.