Impact of freeze-thaw cycles on loess microstructure: A comparison of fine-grained and coarse-grained soils

IF 3.8 2区工程技术 Q1 ENGINEERING, CIVIL

Cold Regions Science and Technology Pub Date : 2025-09-25 DOI:10.1016/j.coldregions.2025.104701

Chongyang Gao, Zhifeng Wu, Rong Chen, Yanchen Ma

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Abstract

The alterations in the microstructure of loess induced by freezing-thawing (FT) processes were crucial for assessing damage to engineering structures in regions affected by seasonal frost. In this study, a series of indoor tests, including freezing-thawing cycles (FTCs), mercury intrusion porosimetry (MIP) tests, and scanning electron microscopy (SEM) observations, were conducted to compare the development patterns of microstructural characteristics between fine-grained and coarse-grained loess. Prior to any FTC test, all loess specimens were prepared with the same initial void ratio (e), although they exhibited significantly different initial pore structures. The results indicated that fine-grained loess tended to develop more pronounced cracks with an increasing number of FTCs, while the surfaces of coarse-grained loess often displayed ice crystals and unevenness. Additionally, the variation in the content of medium and large pores (>0.4 μm) in fine-grained loess was more pronounced than in coarse-grained loess during the FT process. The evolution of microstructural parameters in loess specimens was associated with both FTCs and loess type. The microstructural characteristics of the loess specimens were reflected in changes to micro-parameters such as relative pore content, peak value (Pm), dominant pore diameter (Dm), fractal dimension (D) and particle size distribution. After undergoing more than ten FTCs, the microstructural characteristics of the different loess types tended to stabilize, yet they still retained some initial structural features. These research findings contribute to a better understanding of the failure mechanisms of FT on loess with varying initial structures, thereby providing a scientific foundation for engineering designs that account for regional differences in loess properties.

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冻融循环对黄土微观结构的影响：细粒土和粗粒土的比较

冻融过程引起的黄土微观结构变化是评估受季节霜冻影响地区工程结构损伤的关键。通过冻融循环（FTCs）、压汞孔隙度（MIP）和扫描电镜（SEM）等室内试验，比较了细粒和粗粒黄土微观结构特征的发育规律。在进行任何FTC试验之前，所有的黄土试样都具有相同的初始孔隙比(e)，尽管它们具有明显不同的初始孔隙结构。结果表明：细粒黄土的裂隙随着FTCs数量的增加而更加明显，而粗粒黄土的裂隙表面往往呈现冰晶和凹凸不平；此外，在FT过程中，细粒黄土中、大孔隙（>0.4 μm）含量的变化比粗粒黄土更为明显。黄土试样微观结构参数的演化与黄土类型和FTCs有关。黄土试样的微观结构特征主要体现在相对孔隙含量、峰值（Pm）、优势孔径（Dm）、分形维数(D)和粒度分布等微观参数的变化上。不同类型黄土在经历了十多次FTCs后，其微观结构特征趋于稳定，但仍保留了一些初始结构特征。这些研究成果有助于更好地理解不同初始结构黄土上FT的破坏机制，从而为考虑黄土性质区域差异的工程设计提供科学依据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Cold Regions Science and Technology 工程技术-地球科学综合

CiteScore

7.40

自引率

12.20%

发文量

209

审稿时长

4.9 months

期刊介绍： Cold Regions Science and Technology is an international journal dealing with the science and technical problems of cold environments in both the polar regions and more temperate locations. It includes fundamental aspects of cryospheric sciences which have applications for cold regions problems as well as engineering topics which relate to the cryosphere. Emphasis is given to applied science with broad coverage of the physical and mechanical aspects of ice (including glaciers and sea ice), snow and snow avalanches, ice-water systems, ice-bonded soils and permafrost. Relevant aspects of Earth science, materials science, offshore and river ice engineering are also of primary interest. These include icing of ships and structures as well as trafficability in cold environments. Technological advances for cold regions in research, development, and engineering practice are relevant to the journal. Theoretical papers must include a detailed discussion of the potential application of the theory to address cold regions problems. The journal serves a wide range of specialists, providing a medium for interdisciplinary communication and a convenient source of reference.