【摘要】 为揭示高速铁路路基下伏岛状多年冻土工程特性及时变规律，以新建哈伊高铁日月峡车站试验段岛状多年冻土为研究对象，开展多年冻土热物理参数测试、融沉、融化压缩及静三轴蠕变试验，获取不同含水率、温度及荷载条件下冻土的工程特性参数，系统分析岛状多年冻土融沉、融化压缩及蠕变特性，建立基于水热耦合理论的多年冻土分阶段时变模型，揭示岛状多年冻土路基的温度和变形演化规律。研究结果表明：岛状多年冻土的融沉系数与含水率呈正相关，融化压缩系数与干密度呈负相关，蠕变变形受土质影响显著，随温度和含水率增加呈增大趋势；三阶段时变模型能够较好计算路基岛状多年冻土退化过程中的融沉、压缩及蠕变变形；岛状多年冻土退化呈显著的时空差异性，地基多年冻土退化主要集中在路基填筑区域下方，在第7年时，路基下伏岛状多年冻土全部融化，蠕变、融沉、融化压缩变形均趋于稳定。研究成果将为多年冻土区高速铁路路基设计、施工及长期稳定性评估提供理论依据与技术支撑。更多还原

【Abstract】 To reveal the engineering properties and time-dependent behavior of the underlying sporadic island-shaped permafrost beneath high-speed railway embankments, this study centered on the permafrost in the test section of Riyuexia Station on the newly constructed Harbin—Yichun High-speed Railway. Tests on thermal property parameters, thaw settlement, thaw compression, and static triaxial creep were conducted on the permafrost. Engineering characteristic parameters of the permafrost under different moisture contents, temperatures, and loading conditions were obtained. A systematic analysis was conducted on the thaw settlement, thaw compression, and creep characteristics of the island-shaped permafrost. A staged time-dependent model for permafrost was established based on hydro-thermal coupling theory, revealing the temperature and deformation evolution patterns of the embankment overlying island-shaped permafrost. The results indicate that the thaw settlement coefficient of island-shaped permafrost is positively correlated with moisture content, while the thaw compression coefficient is negatively correlated with dry density. Creep deformation is significantly influenced by soil type and increases with rising temperature and moisture content. The three-stage time-dependent model can effectively calculate the thaw settlement, compression, and creep deformations during the degradation process of the island-shaped permafrost beneath the subgrade. The degradation of the underlying island-shaped permafrost exhibits significant spatiotemporal heterogeneity, primarily concentrated beneath the embankment center. By the 7th year, all the permafrost directly beneath the embankment has melted, and the creep, thaw settlement, and thaw compression deformations all tend to stabilize. The research findings will provide a theoretical basis and technical support for the design, construction, and long-term stability assessment of high-speed railway embankments in permafrost regions.更多还原