JIANG Hai-bo, LIU Jian-feng, ZHANG Jun, et al. Experimental study of collapsibility and microstructure characteristics of loess in long-distance water conveyance channels[J]. 2026, 47(1): 61-72.
DOI:
JIANG Hai-bo, LIU Jian-feng, ZHANG Jun, et al. Experimental study of collapsibility and microstructure characteristics of loess in long-distance water conveyance channels[J]. 2026, 47(1): 61-72.DOI: 10.16285/j.rsm.2025.0117.
Experimental study of collapsibility and microstructure characteristics of loess in long-distance water conveyance channels
为探究新疆长距离输水工程建设中黄土的湿陷性问题,以新疆伊犁河长距离输水工程湿陷性黄土为研究对象,开展渠基黄土不同埋深湿陷性、含水率及孔隙比现场监测试验,重点分析渠基黄土湿陷性的空间分布规律。通过室内自重湿陷试验、浸水压缩试验对不同含水率原状黄土的湿陷特征、孔隙结构进行定量测定,采用微观电镜扫描(scanning electron microscope,简称SEM)和颗粒及裂隙图像识别系统,研究不同湿陷次数、不同竖向应力作用下原状黄土湿陷特征与内部微观孔隙结构的关系。研究结果表明:(1)输水渠道黄土的湿陷性主要受含水率控制,含水率越小,微观孔隙结构特征越显著,湿陷变形特征也越大,且具有一定的“剩余”湿陷性。(2)黄土在湿陷变形过程中存在颗粒软化效应和聚合物效应,孔隙结构逐渐减小,引起了较大的湿陷变形,且在低含水率状态时湿陷变形特征更加显著。(3)长距离输水渠道黄土的湿陷性随埋深增大而逐渐减弱,且渠基黄土的湿陷是多次发生的,先期湿陷性较大、后期湿陷性较小,渠基黄土湿陷性具有多阶段特征。
Abstract
To investigate the collapsibility of loess in long-distance water conveyance projects in Xinjiang
comprehensive field monitoring experiments were carried out. The experiments assessed the collapsibility
moisture content
and void ratio of channel foundation loess at various burial depths
using collapsible loess from the Ili River long-distance water conveyance project in Xinjiang as the research subject. Detailed analyses of the spatial distribution patterns of loess collapsibility within the channel foundation loess were conducted. Concurrently
laboratory-based self-weight collapse tests and immersion compression tests were performed to quantitatively evaluate the collapse characteristics and pore structure of undisturbed loess across different moisture levels. By integrating scanning electron microscope (SEM) and particle and crack image recognition systems
the study explored the relationship between the collapse characteristics and the internal microscopic pore structure of undisturbed loess under varying collapse frequencies and vertical stress conditions. The results show that: (1) The collapsibility of the loess in the water transport channel is primarily controlled by the moisture content. Lower moisture content correlates with more pronounced micro-pore structure characteristics and greater collapsibility deformation
indicating a certain level of “residual” collapsibility. (2) The collapsible deformation process of loess exhibits particle softening and polymer effects
leading to a gradual decrease in pore structure and significant collapsible deformation. The characteristics of collapsibility deformation are more pronounced in a low moisture content state. (3) The collapsibility of loess in long-distance water conveyance channels gradually decreases with increasing burial depth. Additionally
the collapsibility of loess in the canal base occurs multiple times
being greater in the early stages and smaller in the later stages.