Effect of Dry-wet Cycle on the Formation of Loess Slope Spalling Hazards

Zhang, Yuyu; Ye, Wanjun

doi:10.28991/cej-0309133

Cited by 18 publications

(3 citation statements)

References 26 publications

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“…However, there are also some differences. Ye et al 17 showed that there were numbers of cracks and pitting on the surface of loess samples after three cycles, while the vegetation concrete substrate showed cracks on the surface after 12 cycles because cement was added into it. Previous studies 8 have shown that the gelling material produced by the cement hydration reaction could reduce the pore volume of the substrate and increase the inter-particle connection.…”

Section: R E T R a C T E D Discussionmentioning

confidence: 99%

RETRACTED: The evolution of structure properties of vegetation concrete under freeze–thaw cycles

Gao

Liu

et al. 2020

International Journal of Electrical Engineering & Education

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Vegetation concrete is a typical artificial composite soil commonly used for ecological restoration on slopes. The strength and stability of vegetation concrete would be reduced when it is used in areas where freeze–thaw cycles occur frequently. For exploring the changes of structural properties of vegetation concrete under freeze–thaw cycles, an indoor simulation experiment of vegetation concrete samples containing 25 and 30% water content was carried out, so as to test the changes of specimen surface, volume, ultrasonic wave velocity, shearing strength, and microscopic structure. The microstructural parameters were analyzed quantitatively with Image-Pro Plus software. The experimental results indicated that as cycles of freeze–thaw grow, the macroscopic changes of samples included steadily rising surface crack rate, increasing first and then decreasing volume, greatly reducing ultrasonic wave velocity and gradually decreasing shear strength. The inner structure of samples slowly deteriorated from overall dense to dispersed with decreasing cement hydration crystals, pores resulting from dispersion and destruction of bulky grains, higher surface porosity, and smoother particles in microscopic aspect. When compared with samples containing 25% water content, the microstructure of the 30% water content sample was more affected by the freeze–thaw cycle, and its structural weakening effect was more obvious. Reduced cement hydration crystals, lower inter-particle bonding force, and increase in the number of large pores were the main causes of degradation of vegetation concrete structure. Electrical engineering students can refer to the analysis methods in this paper to evaluate the structural performance of any electrical engineering material.

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Section: R E T R a C T E D Discussionmentioning

confidence: 99%

RETRACTED: The evolution of structure properties of vegetation concrete under freeze–thaw cycles

Gao

Liu

et al. 2020

International Journal of Electrical Engineering & Education

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“…Experimental studies have shown that the strength and erosion resistance of soil significantly decreases after FT cycles, and continuous FT action exacerbates the degradation, which leads to high erodibility and denudation sensitivity under thawing (Liu et al, 2017; Wang et al, 2020). Based on the laboratory mechanical tests of undisturbed and remolded loess after FT cycles, the loess cohesion was reported to decrease exponentially with the FT action, while the variation range of internal friction angle was limited (Xu, Ren, et al, 2018; Ye et al, 2012). Research on the microstructure of frozen soil has revealed the micromechanical properties of soil via microscopic observations (Qi et al, 2006), showing FT cycles to destroy the larger aggregates in soil (Song et al, 2017; Xiao et al, 2019), break the connection between the particles, gradually weaken the bonding strength and decrease (increase) the large (small) pores (Ni & Shi, 2014; Xu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Study on thermal‐hydro‐mechanical coupling and stability evolution of loess slope during freeze–thaw process

Qin,

Li,

Yang

et al. 2024

Earth Surf Processes Landf

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Disasters occurring at loess slopes in seasonal frozen regions are closely related to changes in the thermo‐hydro‐mechanical (THM) state in loess by freeze–thaw (FT) action. Current research on FT‐induced soil slope failure focuses on frozen stagnant water effects, while the intrinsic connection between the FT‐induced stagnant water effect and soil strength deterioration remains unclear. In this study, by taking the FT‐induced loess slope failure as an example, field surveys, boreholes, exploratory wells, and 3D topographic mapping were used to reveal the landslide features and stratigraphic information; Furthermore, the temporal and spatial variation of water and heat in loess slope was revealed by on‐site monitoring data; A THM coupled model of frozen soil was established using COMSOL Multiphysics simulation software to reconstruct the frozen stagnant water process of shallow loess slope, as well as the influence of THM field on loess landslide. The results show that the effects of FT in the seasonally frozen region occurred in the shallow layer of the loess slope. The water‐ice phase transition during FT process broke the phase equilibrium of loess. Numerical calculations and field monitoring indicated a continuous migration of water to the freezing front, creating a water‐enriched zone inside the loess. Both the impact of the frozen stagnant water and changes in the stress field led to the degradation of loess structure and reduced the strength properties, thus threatening the stability of the loess slope. The study results can contribute to an in‐depth understanding of the mechanism underlying FT loess landslides in seasonal frozen regions, and provide a scientific basis for the evaluation and prevention of FT landslides.

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“…The temperature differences generated by the short-term diurnal and long-term seasonal changes have resulted in a continuous freeze-thaw cycle, deteriorating the physical and mechanical properties of the soil [3][4][5]. In addition, the impacts of human engineering activities have led to frequent spalling, landslides, and other common issues on the loess cut-slopes in the region, seriously harming the ecological environment along the loess cut-slopes and impeding the coexistence of humans and nature [6][7][8]. Therefore, understanding how the loess in northern Shaanxi degrades during freeze-thaw cycles and identifying the destructive influences on loess cut-slopes could have significant theoretical and practical implications for the engineering design and management of loess cut-slopes in areas with seasonally frozen soil.…”

Section: Introductionmentioning

confidence: 99%

Effect of Freeze–Thaw Cycles and Initial Water Content on the Pore Structure and Mechanical Properties of Loess in Northern Shaanxi

Pan

Yang

et al. 2023

Sustainability

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Spalling disease caused by freeze–thaw cycles often occurs on the loess cut-slopes in northern Shaanxi. The deterioration of the pore structure and mechanical strength of loess under a freeze–thaw environment is one of the critical reasons underlying the occurrence of spalling disease in the slopes. In order to explore the effects of freeze–thaw cycles on the pore structure and the mechanical strength of loess, four initial water contents (7%, 9%, 12%, and 14%) and six freeze–thaw cycles (zero, one, three, five, 10, and 20) were considered in this study. Nuclear magnetic resonance (NMR) and triaxial compression tests were carried out to analyze and reveal the mechanisms of effect causing the deterioration of the soil strength that affects the stability of loess cut-slopes. The results showed that the porosity growth increased with the initial water content and continued to increase during the freeze–thaw process until a later stage of the freeze–thaw cycle, when it gradually stabilized. The stress–strain curves were primarily influenced by the number of freeze–thaw cycles, the initial water content of the samples, and the confining pressure. Both the cohesion and the internal friction angle exhibited a decay law that showed a significant decrease, then a slow decrease, and finally stabilization during the freeze–thaw process. Small and micropores were predominant among the pore structures of the loess, while medium pores were the second most common, and large pores were the least common. With the increase in the initial water content, the pores transformed from micropore structures to medium and large pore structures. The soil strength deterioration was primarily driven by the phase changes of the pore water, as well as the water migration during the freeze–thaw process. This study will be beneficial for identifying the characteristics and types of freeze–thaw disease in cut-slope engineering in seasonally frozen loess areas and providing a theoretical reference and design basis for achieving green and sustainable development in slope engineering, management, and maintenance.

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Effect of Dry-wet Cycle on the Formation of Loess Slope Spalling Hazards

Cited by 18 publications

References 26 publications

RETRACTED: The evolution of structure properties of vegetation concrete under freeze–thaw cycles

RETRACTED: The evolution of structure properties of vegetation concrete under freeze–thaw cycles

Study on thermal‐hydro‐mechanical coupling and stability evolution of loess slope during freeze–thaw process

Effect of Freeze–Thaw Cycles and Initial Water Content on the Pore Structure and Mechanical Properties of Loess in Northern Shaanxi

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