X-ray micro-computed tomography (μ-CT) for 3D characterization of particle kinematics representing water-induced loess micro-fabric collapse

Yu, Bo; Fan, Wen; Fan, Jiangtao; Dijkstra, Tom; Wei, Ya-ni; Wei, Tingting

doi:10.1016/j.enggeo.2020.105895

Cited by 32 publications

(9 citation statements)

References 35 publications

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“…X-ray microtomography (μ-CT) has experienced rapid development in recent decades and has become increasingly popular for the characterization of 3D loess microstructure features (e.g., Deng et al, 2021;Wei et al, 2019Wei et al, , 2020Yu et al, 2020Yu et al, , 2022. A spatial resolution of approximately 1 μm proves to be adequate for the characterization of most skeleton particles and inter-particle/ aggregate pores within loess.…”

Section: Stokes' Diameter Considermentioning

confidence: 99%

A new method for determining loess particle size distribution based on ‘core + clothes’ structure

Zhou

et al. 2023

Earth Surf Processes Landf

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The particle size distribution (PSD) of loess particles and agglomerates is the key factor determining the microstructure of loess. The PSD largely determines many physical and mechanical properties such as mechanical strength, deformation characteristics and permeability of loess. In this paper, we combined image processing, geometric measurements and statistical methods to quantitatively characterize the scanning electron microscopy (SEM) images of loess. A new method based on the ‘core + clothes’ structure is proposed to determine the PSD. The developed Gaussian mixture model is applicable to describe the overall distribution of the image pixel density. Determining pixel density distribution and particle boundary allows for the measurement of various geometric parameters. The comparison analyses suggest that the sieve‐hydrometer method has a well‐developed test procedure; however, the measured particle size is limited to 0.075 mm. The laser diffraction method is simple and fast, yet only weak agglomerates can be dispersed, and very fine particles are influenced by size data conversion theory and light source parameters. X‐ray microtomography has the advantage of a non‐destructive sample preparation and intuitive process. However, the results are greatly affected by the parameter settings and segmentation algorithm, and the segmentation effect is poor for particles with a size smaller than 12 μm. The new image processing technique developed in this study improves the limitation of the measurement results via changes in the loess state (water content, stress level). Moreover, different PSDs can be determined according to the variation of functional units. This work is of great significance for the study of numerous properties related to the loess state.

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Section: Stokes' Diameter Considermentioning

confidence: 99%

A new method for determining loess particle size distribution based on ‘core + clothes’ structure

Zhou

et al. 2023

Earth Surf Processes Landf

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“…The key components of the apparatus are shown in Fig. 1(a) and the principle is similar to that of a strain-controlled laboratory collapse test (Yu et al, 2020). In order to apply load on the sample, the loading head vertically compresses the sample at a controllable slow rate and the applied pressure is simultaneously recorded.…”

Section: Experimental Set-up and Test Programmementioning

confidence: 99%

“…In this paper, we report on experimental evidence of specially designed tests that show pore structure evolution during loess collapse using the μ-CT technique. Collapse tests were carried out on a loess sample of several millimeters in size using an in-house built apparatus (described in detail in Yu et al, 2020). The 3D pore structure within the same sample before and after collapse were extracted and analysed.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous evolution of pore structure during loess collapse: Insights from X-ray micro-computed tomography

Fan

Dijkstra

et al. 2021

CATENA

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“…Numerous studies have adopted these methods to qualitatively investigate the microstructure of loess, including its particle, pore, and contact characteristics, and an increasing number of studies have quantitatively analyzed the loess microstructure in terms of size, shape, and arrangement, by combining these methods with image processing techniques (Deng et al 2020;Giménez et al 2012;Assallay 1998;Gao 1988). Recently researchers began to analyze the three-dimensional (3D) loess microstructure with the development of X-ray CT that can provide nondestructive testing (Li and Shao 2020; Yu et al 2020;Wei et al 2020;Li et al 2019;Wei et al 2019;Li et al 2018). However, great efforts are still required, especially in the aspect of 3D quantitative study of loess microstructure.…”

Section: Introductionmentioning

confidence: 99%

“…However, most of the previous works on loess microstructure by CT were conducted at resolution of dozens of micrometers, which are insu cient to identify particles. Recently, a limited number of studies investigated the microstructure of loess at particle resolution by using X-ray micro-computed tomography (Yu et al 2020;Wei et al 2020;Wei et al 2019). Nevertheless, a systematic analysis of the loess microstructure at the micrometer scale is still rare.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Study of Loess Microstructure At Micrometer Scale Via X-Ray Computed Tomography

Yuan¹,

Fan²

2021

Preprint

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The macroscopic properties of loess are significantly controlled by its microstructure. Quantitative analysis of loess microstructure is essential for modeling the microstructure and further incorporating the microstructural effects into geotechnical practice. However, loess has a multi-scale microstructure ranging from nanometer to millimeter scales, and researches at the particle resolution are still inadequate. This study systematically investigates the micrometer-scale microstructure of loess from Jingyang, China, via X-ray computed tomography and the image segmentation method that was explored for loess. The statistical analyses of three-dimensional (3D) microstructure reveal that the particle size follows the Weibull distribution, and the distributions of pore and pore throat sizes obey the gamma distribution. Most particles are blade-shaped, with a peak length ratio of (1.53–1.64):1.28:1. The particles are oriented in the polar directions but not azimuthally, in a spherical coordinate system, exhibiting a transversely isotropic structure. The quantitative microstructures of the loess and paleosol samples were slightly different irrespective of the large aggregates developed in paleosol sample. Moreover, the representative elementary volume obtained through porosity is also applicable for the analysis of microstructural parameters such as size distribution, shape factor, orientation angle, and pore connectivity. Besides, the two-dimensional (2D) distributions of the particle, pore, and pore throat sizes agree with the 3D distributions, except that the former were marginally smaller. However, the 2D sectional analysis of shape, arrangement, and pore connectivity cannot adequately represent the 3D characteristics.

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X-ray micro-computed tomography (μ-CT) for 3D characterization of particle kinematics representing water-induced loess micro-fabric collapse

Cited by 32 publications

References 35 publications

A new method for determining loess particle size distribution based on ‘core + clothes’ structure

A new method for determining loess particle size distribution based on ‘core + clothes’ structure

Heterogeneous evolution of pore structure during loess collapse: Insights from X-ray micro-computed tomography

Quantitative Study of Loess Microstructure At Micrometer Scale Via X-Ray Computed Tomography

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