水土保持通报2026，Vol.46Issue(2)：32-42,11.DOI:10.13961/j.cnki.stbctb.2026.02.001
冻融循环条件下伊犁地区滑坡黄土湿陷特性及微观机理
Collapsibility characteristics and microscopic mechanisms of loess in Ili region under freeze-thaw cycles
摘要
Abstract
[Objective]The mechanisms through which seasonal freeze-thaw cycles,coupled with initial water content,attenuate the collapsibility of Ili loess were revealed,and a quantitative relationship between microstructural reconfiguration and macroscopic collapsibility variations was established,in order to provide a theoretical basis for prevention and control of loess landslides in seasonally frozen soil regions.[Methods]Freeze-thaw cycling tests were performed on samples with different initial water contents and cycle numbers,accompanied by laboratory collapsibility tests and scanning electron microscope(SEM)observations.Image and statistics-based analyses were conducted to quantitatively characterize microscopic parameters such as pore size distribution,directional frequency,pore abundance,and pore fractal dimension.Correlations between these parameters and the collapsibility coefficient were established,forming an integrated macro-micro analytical framework.[Results]① The collapsibility coefficient decreased significantly with an increase in freeze-thaw cycles for all water contents,and samples with lower water contents were more sensitive.For loess with a water content of 14.2％,the peak collapsibility coefficient decreased from 0.094 to 0.084 after nine cycles,a reduction of approximately 10.6％.For loess with a water content of 20.2％,the peak collapsibility coefficient decreased from 0.079 to 0.076 after nine cycles,a reduction of about 3.8％.② Freeze-thaw cycles weakened interparticle cementation and altered particle connections and arrangement,thereby driving internal structural reorganization toward a new stable state.③ The pore system underwent systematic evolution.The proportion of large pores declined,the pore-size spectrum became finer and more uniform,pore directions were re-arranged,and both pore abundance and pore fractal dimension changed accordingly.④ The microstructural statistical patterns were consistent with qualitative observations and the macroscopic evolution of collapsibility.[Conclusion]Freeze-thaw cycles reduce interparticle bonding and remodel the pore-particle structure.Consequently,the reduction of large pores and changes in fractal dimension constitutes the core mechanisms driving the macroscopic weakening of collapsibility.Based on this,a physical process model of'freeze-thaw → microstructural reconfiguration →collapsibility response'is established,providing theoretical support for the monitoring and prevention of loess landslides in seasonally frozen soil regions such as the Ili area.关键词
冻融循环/湿陷特性/扫描电镜/微观机制Key words
freeze-thaw cycle/collapsibility characteristics/scanning electron microscope/microscopic mechanisms分类
天文与地球科学引用本文复制引用
白一兵,张紫昭,徐元鹏,张力帆..冻融循环条件下伊犁地区滑坡黄土湿陷特性及微观机理[J].水土保持通报,2026,46(2):32-42,11.基金项目
国家自然科学基金项目"伊犁谷地冰雪融水叠加降雨入渗黄土滑坡形成机理与预警判据"(42367021) （42367021）
新疆维吾尔自治区天山英才培养计划"天山北坡矿山开采地质灾害-水文地质-生态环境耦合互馈机制及其工程地质意义"(2023TSYCCX0010) （2023TSYCCX0010）
