Microstructure of Compacted Loess and Its Influence on the Soil‐Water Characteristic Curve

Xie, Xiao; Li, Ping; Hou, Xiaokun; Li, Tonglu; Zhang, Guowei

doi:10.1155/2020/3402607

Cited by 14 publications

(10 citation statements)

References 25 publications

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“…is may be because the micropores decreased very slightly with the increasing LAT contents at that content higher than 1%. Generally, k sat is dominated by the micropores in soil [18,30]. us, as the LAT content increased from 1% to 9%, it seems that the LAT content did not affect k sat dramatically and the soil density (void ratio) was dominated.…”

Section: Mltl and CL Soilsmentioning

confidence: 91%

Effect of Admixture on the Hydraulic Conductivity of Compacted Loess: A Case Study

Pan

Zhang

et al. 2020

Advances in Civil Engineering

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Hydraulic characteristic of the exposed ground plays an important role in the construction of “sponge city,” which is a popular concept in the world recently. Loess soil, which is a common geomaterial in its distribution area approximately 9.3% of the world’s land surface, usually could not satisfy the engineering requirement only by compacting without any other treatments. This paper aims to investigate the effect of a natural geomaterial, lateritic soil, which is more economical and environmental than the traditional admixtures such as cement and lime, on the saturated hydraulic conductivity (ksat) of compacted loess. A series of falling-head permeability tests on pure loess and lime-treated loess were carried out firstly for comparison; then lime-treated loess mixed with different contents of lateritic soil was tested. To verify the availability of the coverage of high density lateritic soil on pure loess for antipermeability, which is a common treatment in local area, tests of different thickness of the coverage were conducted. The test results revealed that the admixture of lime could obviously decrease ksat of pure loess and 3% might be the most economical content. An empirical algorithm was proposed based on the results to estimate ksat of lime-treated loess of which the lime content is out of the scope studied in this paper, and it would be useful for engineering design and numerical simulation of safety evaluation. The addition of lateritic soil in the 3% lime-treated loess could further decrease ksat and its performance for antipermeability was better than increasing the lime contents simply. The coverage of high density lateritic soil could also improve the antipermeability of loess, and thickness at least of 30 mm was suggested for engineering practice.

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Section: Mltl and CL Soilsmentioning

confidence: 91%

Effect of Admixture on the Hydraulic Conductivity of Compacted Loess: A Case Study

Pan

Zhang

et al. 2020

Advances in Civil Engineering

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“…The SWCC cross phenomenon shows that despite variations in the dry density of compacted loess, there is always a critical point at which loess of different dry densities have the same volumetric water content and matrix suction. This critical point is only affected by the particle size, not the particle spacing (Xie et al 2020).…”

Section: Swccmentioning

confidence: 95%

The Influence of Drying-Wetting Cycles on the Suction Stress of Compacted Loess and the associated Microscopic Mechanism

Nie¹,

Ni²,

Li³

et al. 2021

Preprint

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In order to better understand and analyze the unsaturated stability of loess fillings, it is necessary to study the changes in suction stress before and after the drying-wetting cycles. In this study, the soil-water characteristic curve (SWCC) of compacted loess before and after drying-wetting cycles was tested using the filter paper method. Then, the suction stress was calculated and the microstructure of the loess sample was determined by the scanning electron microscope（SEM）and nuclear magnetic resonance (NMR). The results showed that the drying-wetting cycles had an important influence on the suction stress characteristic curve (SSCC) and microstructure of compacted loess. The change in suction stress before and after the drying-wetting cycles can be explained by the loess microstructure. The drying-wetting cycles did not significantly change the basic trend of the compacted loess's suction stress, but it increased the porosity and the diameter of the dominant pore (i.e., the inter-aggregate pore) of the sample, and reduced the suction stress when the same matrix suction was applied. The main significant change in suction stress with matrix suction occurred within the range of the dominant soil pores. The larger the diameter of the dominant pore, the smaller the suction stress under the same matrix suction. In addition, this study also proposes a new method for calculating suction stress based on the pore size distribution（PSD） parameters, which is more convenient than traditional calculation methods based on SWCC parameters.

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“…The SWCC cross phenomenon shows that, despite variations in the dry density of compacted loess, there is always a critical point at which loess of different dry densities have the same volumetric water content and matric suction. This critical point is affected by the particle size and the specific surface of the particle, not the particle spacing [38].…”

Section: Swccmentioning

confidence: 97%

The Influence of Drying-Wetting Cycles on the Suction Stress of Compacted Loess and the Associated Microscopic Mechanism

Nie

et al. 2021

Water

View full text Add to dashboard Cite

To better understand and analyze the unsaturated stability of loess filling body, it is necessary to study the changes in suction stress before and after the drying-wetting cycles. In this study, the SWCC of compacted loess before and after drying-wetting cycles was tested using the filter paper method. Then, the suction stress was calculated and the microstructure of the loess sample was determined by the SEM and NMR. The results showed that the drying-wetting cycles had an important influence on the SSCC and microstructure of compacted loess. The change in suction stress before and after the drying-wetting cycles can be well explained by the loess microstructure. The drying-wetting cycles did not significantly change the basic trend of the compacted loess’s SSCC, but it increased the porosity and the dominant pore diameter of loess, and reduced the suction stress under the same matric suction. The main significant change in suction stress with matric suction occurred within the range of the dominant soil pores. The larger the dominant pore diameter, the smaller the suction stress under the same matric suction. In addition, this study proposes a new method for calculating suction stress based on the PSD parameters.

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Microstructure of Compacted Loess and Its Influence on the Soil‐Water Characteristic Curve

Cited by 14 publications

References 25 publications

Effect of Admixture on the Hydraulic Conductivity of Compacted Loess: A Case Study

Effect of Admixture on the Hydraulic Conductivity of Compacted Loess: A Case Study

The Influence of Drying-Wetting Cycles on the Suction Stress of Compacted Loess and the associated Microscopic Mechanism

The Influence of Drying-Wetting Cycles on the Suction Stress of Compacted Loess and the Associated Microscopic Mechanism

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