Experimental study on the disintegration of loess in the Loess Plateau of China

Li, Xian; Wang, Li; Yan, Yongli; Hong, Bo; Li, Lin-Cui

doi:10.1007/s10064-018-01434-6

Cited by 48 publications

(27 citation statements)

References 40 publications

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“…Compared with other frequently-studied types of erodible soils such as loess and residual soils, the disintegration feature of dispersive soil exhibits both similarity and uniqueness. For instance, both dispersive soil and loess show a strong ω dependence; in Li et al (2019), an increase in ω from approximately 5% to 9% led to faster disintegration, which echoes the Mode 1 in this study. In addition, the silt-dominant particle composition is believed to facilitate the dispersion and disintegration of dispersive soil, whereas Liu, Zhang, Kong, Wang, and Lu (2022) had reservations about the applicability of this law on weathered granite residual soil.…”

Section: Comparison With Typical Erodible Soilssupporting

confidence: 78%

Feature and mechanism analysis of dispersive soil disintegration impacted by soil water content, density, and salinity

Han

Wang

2023

European J Soil Science

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Dispersive soil has caused innumerable water‐induced erosion failures of earthen structures in arid regions up to now, among which disintegration, as the first response process, is commonly deemed as the primary inducement but with inadequate understanding. In this study, the disintegration characteristics of a compacted dispersive lean clay with sand were investigated by carrying out laboratory disintegration tests under a water immersion regime. Soil mass water content (ω), dry density (ρd) and total soluble salt content (η) were considered. Results suggest that for dispersive soil, (1) the disintegration process exhibited two distinct modes, which was divided by the ω near the optimum water content; (2) higher ρd delayed disintegration monotonously; (3) increasing η first weakened and then enhanced the disintegration, in which pattern the η at the inflection point increased with increasing ρd, showing a density dependence. Evolutions of representative soil morphology were illustrated. More importantly, the underlying influential mechanism of ω and η to disintegration were elaborated emphatically: (1) the initial clay dispersion level, soil consistency change, and conceptual “constraint force” exerted by soil matric suction jointly determine the disintegration modes; (2) increasing η makes the soil pore solution concentration higher and microstructure simpler, competition between the two leads to nonmonotonic change patterns of disintegration completion time (Td) and defined velocity (Vd); the interactive effect of ρd and η manifests that η produces an additional influence on the base of microstructure created by ρd. Finally, the grey relation entropy analysis was introduced to evaluate the contributions of the three test variables to Td and Vd. The obtained results and proposed perspectives are expected to be conducive to a deeper comprehension of the same or relevant behaviours of dispersive soils in the presence of water, so as to provide new insights for the targeted prevention and control of dispersive soil catastrophes. Highlights Disintegration of dispersive soil shows two distinct water content‐dependent modes. Soil salinity has a two phase impact on disintegration of dispersive soil. Dry density and soil salinity interact affecting disintegration. Relationship between soil dispersion and disintegration is elaborated.

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Section: Comparison With Typical Erodible Soilssupporting

confidence: 78%

Feature and mechanism analysis of dispersive soil disintegration impacted by soil water content, density, and salinity

Han

Wang

2023

European J Soil Science

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“…). The flow could easily erode the well-developed vertical joints (Xu, 1999) and then cause the expansion and disaggregation of the surrounding loess particles (Li X.-A. et al, 2019b), by inference, forming loess caves (Hu et al, 2020).…”

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confidence: 99%

Interaction Between Animal Burrowing and Loess Cave Formation in the Chinese Loess Plateau

et al. 2021

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Although the interactions between biotic and geomorphic processes usually occur on small spatial and short temporal scales, many of the mechanisms remain to be investigated. This study provides the first direct evidence of the interaction between biotic burrowing and loess cave formation in the Chinese Loess Plateau (CLP). The study area is the Qingshui Valley in the western CLP, near Lanzhou. We surveyed the target site (with an area of ∼13,367 m2) four times from Jul 2019 to Dec 2020, using an unmanned aerial vehicle (UAV). High resolution UAV images enabled us to determine the temporal and spatial dynamics of biotic burrowing and loess caves. The results show that loess caves tended to develop down valley below collapses, while animal burrows were preferentially located upslope away from collapses. Despite the distinct “topographic niches” for both biotic and abiotic processes, we observed an interaction between the two processes in space when tracking their temporal dynamics. Three out of seven new loess caves were in the process of formation at typical “topographic niches” of animal burrows and there was a significantly high animal burrow density around these three caves before their initiation. These results indicate that the three caves were directly initiated from animal burrows and/or developed under the influence of biotic activities. Therefore, biotic burrowing promotes the spatial heterogeneity of loess cave distribution. We also found significant decreases in animal burrow density surrounding the newly-formed loess caves after their initiation. This may reflect a risk avoidance strategy of animal burrowing, which causes animals to avoid areas of recent mass movement (i.e., collapses and new caves). The formation and expansion of loess caves can dictate the distribution of active areas of biotic disturbance. Our results demonstrate a clear interaction between biotic burrowing and loess cave formation, and they emphasize the role of biological agents as a mechanism for the formation of loess caves, which enrich the understanding of searching fingerprints of life during landscape evolution.

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“…At present, there is no standard for clayey-soil-disintegrating apparatus. In this paper, the clayey-soil-disintegrating apparatus developed by Wang et al [31] and Li et al [32] was used after some modifications. The instrument is composed of inner and outer cylinders, as shown in Figure 3.…”

Section: Disintegration Test Schemementioning

confidence: 99%

Permeability and Disintegration Characteristics of Composite Improved Phyllite Soil by Red Clay and Cement

Zhao

Yang

et al. 2022

Minerals

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The bearing capacity of the phyllite soil subgrade can be greatly improved by red clay, but the water stability of the modified soil is still poor. Hence, the blended soil has been found to be unsuitable for the construction of high-speed railways. This paper proposes an innovative scheme, by adding appropriate amounts of cement and red clay concurrently, to improve phyllite soil, which achieves a higher bearing capacity of the subgrade immediately after compaction, while also solving the problem of insufficient water stability. Laboratory tests of the permeability and disintegration characteristics of phyllite soils improved by cement, red clay, and both were carried out. The test results show that the permeability coefficient and maximum disintegration rate of soil can be improved effectively by using both red clay and cement. It was found that the optimal combination scheme is to add 3% cement and 40% red clay to phyllite soil by mass. Under the optimal scheme, the permeability coefficient, maximum disintegration rate, and disintegration rate of the improved soil decreased by 90.02%, 90.30%, and 99.02%, respectively, compared with the phyllite soil. The microscopic study shows that the mechanism of red clay blending with phyllite is that the finer particles of red clay infill the pores among the phyllite particles, thus reducing its permeability coefficient. The mechanism of adding cement to the blending soil mainly results from the production of hard-setting new materials and the formation of a cementation network among the soil particles, which not only increases the shear strength of the soil, but also reduces the permeability coefficient and the maximum disintegration ratio of the soil. This work makes full use of the complementary characteristics of red clay and phyllite soil and the advantages of hard-setting new materials, which will provide a new idea for soil improvement of the phyllite soil in the future.

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Experimental study on the disintegration of loess in the Loess Plateau of China

Cited by 48 publications

References 40 publications

Feature and mechanism analysis of dispersive soil disintegration impacted by soil water content, density, and salinity

Feature and mechanism analysis of dispersive soil disintegration impacted by soil water content, density, and salinity

Interaction Between Animal Burrowing and Loess Cave Formation in the Chinese Loess Plateau

Permeability and Disintegration Characteristics of Composite Improved Phyllite Soil by Red Clay and Cement

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