Characteristics of strength and pore distribution of lime-flyash loess under freeze-thaw cycles and dry-wet cycles

Yan, Changgen; Zhang, Zhiquan; Jing, Yanlin

doi:10.1007/s12517-017-3313-5

Cited by 36 publications

(22 citation statements)

References 11 publications

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“…Then, the relationship between the shear strength loss rate and the freeze-thaw damage can be obtained from the Equations (14) and (15).…”

Section: =mentioning

confidence: 99%

“…In order to explore the changes of mechanical properties of loess under the action of freeze-thaw cycles, it is found that the change of water content and the rate of freezing have a great influence on the strength change [9,11,14]. Yan et al [15] studied the unconfined compressive strength and pore distribution characteristics of lime fly ash loess through a series of experiments under freeze-thaw cycles. Xu et al [16] carried out freeze-thaw tests, direct The freeze-thaw cycle is extremely destructive, which can change the internal structure of the loess and weaken its mechanical properties, leading to a decrease in the bearing capacity of the loess and causing engineering disasters.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

Yang

Liu

2020

Water

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The loess landslide in Gaoling District of Xi’an, Shaanxi in China is closely related to the seasonal freeze–thaw cycle, which is manifested by the destruction of pore structure and strength deterioration of the loess body under freeze–thaw conditions. In order to study the relationship between macro-strength damage and pore structure deterioration of saturated loess under freeze–thaw conditions and its influence on the stability of landslides, this paper explores the effect of freeze–thaw cycles on the strength of saturated undisturbed loess through triaxial compression test, and explores the micro-microstructure changes of saturated undisturbed loess through scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). This is to analyze the evolution of the pore structure and strength loss evolution of saturated loess during the freeze–thaw process, and to describe the freeze–thaw damage of saturated undisturbed loess through the change of porosity and strength deterioration. Then, the internal correlation expression between the porosity change and the strength degradation is established to realize the verification analysis of the test data based on the correlation model. The research results show that: (1) As the number of freeze–thaw cycles increases, the peak strength loss rate gradually increases, and the strength deterioration of saturated loess becomes more and more obvious. (2) The freeze–thaw cycle will lead to the development of pores and cracks in the sample, accompanied by the generation of new cracks, which will cause the deterioration of the pore structure of the sample as a whole. (3) The response of strength damage and porosity deterioration of saturated undisturbed loess is roughly similar under the freeze–thaw cycle. The change in porosity can be measured to better reflect the strength deterioration of saturated loess. Therefore, the change of pore structure of undisturbed loess under freeze–thaw cycle conditions is tested by field sampling and indoor tests to reflect the phenomenon of strength deterioration, thereby analyzing the stability of loess slopes.

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“…Then, the relationship between the shear strength loss rate and the freeze-thaw damage can be obtained from the Equations (14) and (15).…”

Section: =mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

Yang

Liu

2020

Water

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“…Two typical weathering processes, dry-wet (D-W) cycles and freeze-thaw (F-T) cycles are common in China's Loess Plateau [27,28], affecting the physical and mechanical properties of its loess [29][30][31], and causing shallow diseases of loess slopes to become more prominent [32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Effect of Dry‐Wet Cycles and Freeze‐Thaw Cycles on the Antierosion Ability of Fiber‐Reinforced Loess

Yan

Wang³

et al. 2021

Advances in Materials Science and Engineering

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Compared with plain soil, polypropylene (PP) fiber-reinforced soil has markedly improved mechanical properties and can be used in slope protection projects. To investigate the reduction law of the antierosion ability parameters of PP fiber-reinforced loess under dry-wet (D-W) cycles and freeze-thaw (F-T) cycles, we took loess from Yan’an, China, mixed them with PP fiber, and did shear strength tests, disintegration tests, and permeability tests under D-W cycles and F-T cycles. The experimental results show that D-W cycles or F-T cycles had a less deteriorating effect on the cohesion, disintegration rate, and permeability coefficient of the fiber-reinforced samples than on plain loess; however, the reduction in their internal friction angle was more obvious. Under D-W cycles or F-T cycles, the cohesion and internal friction angle of the reinforced soil decreased as the number of cycles increased, while the disintegration rate and permeability coefficient increased as the number of cycles increased. The relation between the reduction in the antierosion ability parameters of reinforced soil and the number of D-W cycles or F-T cycles accorded with the hyperbolic function fitting results. The most obvious reduction effect the D-W cycles had on the reinforced soil was on the disintegration rate, followed by cohesion, internal friction angle, and permeability coefficient. The most obvious effect of F-T cycles was also on the disintegration rate, followed by cohesion, permeability coefficient, and internal friction angle. Compared with D-W cycles, F-T cycles had a stronger effect on the reduction in the cohesion, disintegration rate, and permeability coefficient of reinforced soil, but the reduction in the friction angle was greater in D-W cycles.

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“…In cold regions, geological disasters caused by FTC occur frequently and their mechanical mechanisms have received extensive attention [20,21]. Practically, in freezing and thawing environments, the fundamental causes of change in the macroscopic mechanical properties of soil are changes to its microstructure [7,8,17].…”

Section: Introductionmentioning

confidence: 99%

Shear Strength and Microstructure of Intact Loess Subjected to Freeze‐Thaw Cycling

Liu

Jing

2021

Advances in Materials Science and Engineering

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In the Loess Plateau, seasonal freeze and thaw cause great damage to the mechanical behavior and microstructure of soil, which leads to frequent geological disasters during winter and spring. To investigate the influence of freeze-thaw (FT) cycling (FTC) on the shear strength and microstructure of intact loess, triaxial shear, nuclear magnetic resonance, and scanning electron microscope tests were carried out on soil samples after target FT cycles. The results indicate that the FTC has limited changes to the soil stress-strain curve, but has a significant attenuation effect on the peak deviatoric stress. The peak deviatoric stress was attenuated by FTC but changed insignificantly after ten cycles. The cohesive force decays exponentially with the number of FT cycles, while the internal friction angle increases slightly. Moreover, under FTC, the T2 hydrogen spectra of soil samples showed a multimodal distribution, with the main peak appearing to have two obvious upward shifts that occurred at 6 and 10 FT cycles. Indeed, a depolarization phenomenon related to the directional frequency of soil particles was observed, and the mass fractal dimension of the pore network increased slightly. In an FT environment, the shear strength declines due to accumulated internal microstructural damage. These findings contribute to a better understanding of the response of loess to FTC and provide novel ideas for the prevention of frost damage in loess areas.

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Characteristics of strength and pore distribution of lime-flyash loess under freeze-thaw cycles and dry-wet cycles

Cited by 36 publications

References 11 publications

The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

Effect of Dry‐Wet Cycles and Freeze‐Thaw Cycles on the Antierosion Ability of Fiber‐Reinforced Loess

Shear Strength and Microstructure of Intact Loess Subjected to Freeze‐Thaw Cycling

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