Experimental study of the effect of bound water on the shear strength and structural units of Malan loess

IF 1.3 4区 工程技术 Q3 ENGINEERING, GEOLOGICAL
Zhitao Hao, Xi'an Li, Rongrong Gao, Wei Hu, Jing Zhang, Jun He
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引用次数: 3

Abstract

The structural specificity and hydrological sensitivity of loess have a strong impact on its strength, deformation and long-term stability and safety. This topic is being actively researched and focuses on the macromechanical behaviour of the shear strength of loess and its micromechanisms from the perspective of bound water. In this study, based on the combined determination of isothermal adsorption and the liquid-plastic limit, bound water is analysed qualitatively and quantitatively, and the entire humidity sequence is divided in a new method. The shear strength of Malan loess measured by the direct shear test is also analysed to investigate the relationship between bound water, shear strength and basic structural units. Results show that the Malan loess in the three regions in this paper are approximately the same in terms of adsorption pattern, but at the same humidity, the maximum moisture content (W мг ) from more to less are Chan he (7.13%), Yan'an (6.54%), and Hei fang tai (5.54%), which is related to the clay minerals and their contents in the soil. Also, the change in strength of loess is divided into three stages by the maximum moisture content (W мг ) and plastic limit (W P ) as the characteristic moisture content. The strength change pattern of loess in the three regions is similar throughout the moisture content sequence: all stages show a negative correlation between moisture content and shear strength, but the internal mechanism of each stage is not the same due to the different connection forces between the basic structural units of loess. The change in bound water content caused by the cementation of glue and clay particles also yields certain changes in cohesion, which is linearly fitted to the shear strength and its parameters. Last, the bound water of the soil changes the microstructure of the soil and determines the combination characteristics and contact mode of "core-clothes" in the microagglomerate structure of loess. This study describes the essence of soil-water structural interactions and provides theoretical references for applications in geotechnical engineering fields such as slope protection and road construction.
结合水对马兰黄土抗剪强度及结构单元影响的试验研究
黄土的结构特性和水文敏感性对其强度、变形和长期稳定性与安全性有很大影响。本课题正处于积极的研究阶段,主要从束缚水的角度研究黄土抗剪强度的宏观力学行为及其微观力学。在本研究中,基于等温吸附和液塑性极限的联合测定,对结合水进行了定性和定量分析,并用一种新的方法对整个湿度序列进行了划分。对马兰黄土直剪试验测得的抗剪强度进行了分析,探讨了结合水、抗剪强度与基本结构单元之间的关系。结果表明,三个地区的马兰黄土在吸附模式上大致相同,但在相同的湿度下,最大含水量(WмΓ)从多到少依次为陈河(7.13%)、延安(6.54%)和黑方台(5.54%),这与土壤中粘土矿物及其含量有关。此外,根据最大含水量(WмΓ)和塑性极限(W P)作为特征含水量,将黄土强度的变化分为三个阶段。三个地区黄土的强度变化模式在含水率序列上是相似的:所有阶段的含水率与抗剪强度都呈负相关,但由于黄土基本结构单元之间的连接力不同,每个阶段的内在机制并不相同。由胶水和粘土颗粒的胶结引起的结合水含量的变化也会产生一定的内聚力变化,这种变化与剪切强度及其参数线性拟合。最后,土壤的结合水改变了土壤的微观结构,决定了黄土微团聚体结构中“芯衣”的组合特征和接触方式。该研究描述了土壤-水-结构相互作用的本质,并为边坡防护和道路建设等岩土工程领域的应用提供了理论参考。
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来源期刊
CiteScore
3.40
自引率
14.30%
发文量
66
审稿时长
6 months
期刊介绍: Quarterly Journal of Engineering Geology and Hydrogeology is owned by the Geological Society of London and published by the Geological Society Publishing House. Quarterly Journal of Engineering Geology & Hydrogeology (QJEGH) is an established peer reviewed international journal featuring papers on geology as applied to civil engineering mining practice and water resources. Papers are invited from, and about, all areas of the world on engineering geology and hydrogeology topics. This includes but is not limited to: applied geophysics, engineering geomorphology, environmental geology, hydrogeology, groundwater quality, ground source heat, contaminated land, waste management, land use planning, geotechnics, rock mechanics, geomaterials and geological hazards. The journal publishes the prestigious Glossop and Ineson lectures, research papers, case studies, review articles, technical notes, photographic features, thematic sets, discussion papers, editorial opinion and book reviews.
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