摘要
东北黑土区作为我国重要的商品粮基地,其土壤冻融过程的水热迁移与变形特征直接影响区域粮食安全与生态稳定性。本研究通过室内单向冻融试验、扫描电镜观测及热–水–变形多场耦合模型,系统揭示了多因素驱动下黑土冻融的协同机制。结果表明:未补水条件下,土体升温呈现滞后性与阶段性,表层相变过冷度达1.2~2.5℃;主动补水可提升上层温度2~4℃,冻深缩减28%~35%,削弱地表负温效应。同时,冻结阶段水分场重分布呈“S”型,未冻水含量自上而下递减,融化阶段趋势反转。冻融循环显著改变微观结构,30次循环后孔隙率增长21.62%~546.47%,团聚体破坏率高达99%,且高含水量(>32.3%)样本更易受冻胀作用影响。此外,构建的多场耦合模型(温度与含水量相关系数>0.9)精准预测了冻融响应,揭示了表层草炭黑土冻胀主导、中层渗透差异调控热传导、深层刚性骨架抑制变形的分层机制,建议通过秸秆覆盖、排水措施及低含水量耕作制度提升土壤稳定性。研究成果为黑土区冻融侵蚀动态监测体系构建及保护性耕作优化提供了理论与技术支撑。
The black soil region in Northeast China is an important commercial grain base in China.Hydrothermal migration and deformation of the soil during the freeze-thaw process directly affect regional food security and ecological stability.This study systematically revealed the synergistic mechanism of black soil freeze-thaw under multi-factor driving through indoor unidirectional freeze-thaw experiments,scanning electron microscopy observations,and thermal-water-deformation multi-field coupling models.The results showed that under the condition of no water replenishment,the temperature rise of the soil exhibited hysteresis and periodicity,and the supercooling degree of the surface phase change reached 1.22.5 C;Proactive water replenishment increased the upper layer temperature by 2–4℃,reduced freezing depth by 28%–35%,and weakened the negative temperature effect on the ground surface.At the same time,the water field redistribution during the freezing stage showed an"S"shape,with the unfrozen water content decreasing from top to bottom,and the trend during the melting stage reversing.The freeze-thaw cycle significantly changed the microstructure,with a porosity increased by 21.62%546.47%after 30 cycles,and aggregate destruction rate up to 99%.Moreover,samples with high water content(>32.3%)were more susceptible to freeze-thaw effects.In addition,the constructed multi-field coupling model(temperature and water content correlation coefficient>0.9)accurately predicted the freeze-thaw response,revealing the layered mechanism of surface peat black soil frost heave dominance,middle layer permeability difference regulating heat conduction,and deep rigid skeleton inhibiting deformation.It is recommended to improve soil stability through straw covering,drainage measures,and low water cultivation system.The study results provide theoretical and technical support for the construction of a dynamic monitoring system for freeze-thaw erosion and the optimization of conservation tillage in black soil areas.
作者
徐智超
马敏
陈匀杉
单炜
邓超
吴宽
计静
XU Zhichao;MA Min;CHEN Yunshan;SHAN Wei;DENG Chao;WU Kuan;JI Jing(National Civil Engineering Experimental Teaching Demonstration Center,Hunan City University,Yiyang,Hunan 413002,China;Northeast Permafrost Zone Geological Environment System Field Scientific Observation and Research Station,Ministry of Education,Northeast Forestry University,Harbin 150040,China;Ministry of Water Resources Key Laboratory of River and Lake Source Area Water Ecological Management and Protection,Qinghai University,Xining 810016,China;Hunan Provincial Research Center for Urban Underground Infrastructure Structural Safety and Disaster Prevention Engineering,Hunan City University,Yiyang,Hunan 413002,China;Hunan Provincial Key Laboratory of Digital Urban and Rural Spatial Planning Technology,Hunan City University,Yiyang,Hunan 413002,China;Heilongjiang Provincial Key Laboratory of Disaster Prevention and Mitigation Engineering and Protective Engineering in Colleges and Universities,Northeast Petroleum University,Daqing,Heilongjiang 163318,China;Key Laboratory of Structural Disaster and Control,Ministry of Education,Harbin Institute of Technology,Harbin 150040,China)
出处
《土壤》
北大核心
2025年第5期1152-1167,共16页
Soils
基金
湖南省教育厅优秀青年基金项目(23B0737)
湖南省自然科学基金项目(2025JJ70386)
国家自然科学基金项目(41641024)资助。
关键词
冻融循环
黑土
水热迁移
宏微观变形
多场耦合模型
Freeze-thaw cycle
Black soil
Hydrothermal migration
Macro and micro deformation
Multi-field coupling model
