微观尺度下黄土多级湿陷性研究

A Study on Multi-level Collapsibility of Loess at Microscale

[目的]验证黄土多级湿陷性以及探究微观尺度下黄土的湿陷变形方式,为黄土的湿陷变形机理研究提供科学依据。[方法]分别设计、实施了室内循环加水湿陷试验和相同样品增湿前后微观结构观察试验,并分别对湿陷数据与扫描电镜影像进行分析和对比。[结果]湿陷数据表明,在黄土达到一次湿陷稳定以及去水稳定后,在装置内再次加水会导致试样再次发生明显形变,而黄土的微观结构在湿陷过程中发生了溶解、移动、重组三种变形方式。[结论]黄土结构这种破坏-重组-破坏的动态循环过程是黄土能够发生多级湿陷的内在原因。

[Objective]The multi-level collapsibility of loess was investigated and the way of loess collapsibility deformation was studied at the microscale in order to provide a scientific basis for the study of loess collapsible deformation mechanism.[Methods]We designed and conducted a indoor cyclic collapsibility test,to observe the micro-structure of the same samples under repeated humidification and dehumidification processes.The collapsibility data were analyzed and the scanning electron microscopy images were compared.[Results]The collapsibility data showed that after the loess reached the first collapsibility and water removal stability,adding water into the device would cause the deformation of the sample again.During the collapsibility process,the micro-structure undergone three deformation modes:dissolution,movement and reconstruction.[Conclusion]It is the dynamic process of destruction-reconstruction-destruction of loess structure that leads to multi-level collapsibility of loess.