西北地质2026，Vol.59Issue(2)：46-58,13.DOI:10.12401/j.nwg.2025144
干湿循环作用下人工结构性黄土的变形与结构演变机理研究
Deformation and Structural Evolution Mechanism of Artificial Structured Loess under Wet-Dry Cycles
摘要
Abstract
The seasonal rainfall leads to a frequent wet-dry cycle environment across the China Loess Plateau.This environment often aggravates foundation settlement and collapsible deformation in loess subgrades.This study investigates the coupling mechanism of microstructural damage and macro-deformation evolution under wet-dry cycles.The findings provide a theoretical basis for engineering disaster prevention in loess regions.Arti-ficially structured loess with controllable composition and uniform structure was prepared to simulate natural loess.This experimental approach facilitated the systematic study of the effects of wet-dry cycles(0～9 cycles)on loess.Macro-mechanical behaviors were tested using confined compression and single-line collapsibility methods.Microstructural characteristics were analyzed via Scanning Electron Microscopy(SEM),particle anal-ysis,and X-ray Diffraction(XRD).The test results indicate that wet-dry cycling causes irreversible damage to the loess microstructure.Macroscopically,compressive deformation shows a significant positive correlation with the number of cycles.Conversely,the collapsibility coefficient follows a non-monotonic evolutionary pattern,first increasing and then decreasing.The structural parameters exhibit a non-linear decay characterized by an"initial sharp drop followed by stabilization".The first three cycles constitute the primary structural damage phase;the decay rate slows down significantly during cycles 5 to 9,reaching only about one-quarter of the ini-tial rate.Microscopically,the dissolution and loss of cementing agents cause the soil structure to evolve.The support system transforms from a"strong cementation-large aggregate"structure to a"weak cementation-loose particle"contact system.This loss of cementing agents and the resulting microstructural rearrangement are the essential causes of macroscopic mechanical degradation.In the initial cycles,structural disintegration driven by cementation failure dominates.This significantly enhances collapsibility sensitivity.In later cycles,pore com-paction and structural reorganization increase the soil's resistance to further deformation.Therefore,engineering practices must prioritize waterproofing during the early exposure period of the foundation to prevent sudden set-tlements caused by accumulated structural damage.关键词
干湿循环/压缩变形/湿陷变形/结构性/胶结强度Key words
wet-dry cycles/compressive deformation/collapsible deformation/structural characteristics/cementation strength分类
天文与地球科学引用本文复制引用
张耀,周楚鸿,李祖峰,范新宇,郭培玺..干湿循环作用下人工结构性黄土的变形与结构演变机理研究[J].西北地质,2026,59(2):46-58,13.基金项目
陕西省教育厅服务地方专项研究计划"循环荷载作用下抽蓄电站湿陷性黄土盆库变形特征及控制技术研究"(23JE019),陕西省教育厅服务地方专项研究计划"考虑力学参数演变的降雨型黄土滑坡预报预警技术研究"(23JE018),陕西省教育厅服务地方专项研究计划"测量机器人近地气层大气折射模型研究与软件实现"(22JE018),长江科学院开放研究基金"黄土的宏观力学性质与细观结构特征的关联性研究"(CKWV20231170/KY)联合资助. （23JE019）
