scholarly journals Quantitative Evaluation of Soil Structure and Strain in Three Dimensions under Shear Using X-ray Computed Tomography Image Analysis

2021 ◽  
Vol 7 (11) ◽  
pp. 230
Author(s):  
Shintaro Nohara ◽  
Toshifumi Mukunoki
Keyword(s):  
Computed Tomography ◽  
Image Analysis ◽  
Shear Zone ◽  
Soil Structure ◽  
Three Dimensions ◽  
Image Correlation ◽  
Ct Scanner ◽  
Zone Formation ◽  
X Ray ◽  
X Ray Computed

The objective of this study is to quantitatively evaluate the soil structure behavior when under shear stress to understand the mechanism of shear zone formation using a micro-focus X-ray computed tomography (CT) scanner to visualize the internal samples without causing disturbance. A new image-analysis method was proposed to systematically evaluate the particle length and direction by fitting the particle as an ellipsoid. Subsequently, a direct shear experiment was conducted on soil materials, and shear band was scanned using a micro-focus X-ray CT scanner. After validating the proposed method, the soil structure was evaluated in the shear zone via image analysis on the CT images. Furthermore, the strain inside the specimen was evaluated using digital image correlation. The results showed that a partial change in the particle direction occurred when the volume expansion inside the shear zone exceeded the peak. In addition, the width of the shear zone was ~7.1 times the median grain size of the sand used; however, the region exhibiting a change in the direction of the particles was narrow and confined to the vicinity of the shear plane.

scholarly journals A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3416 ◽  
Author(s):  
Zartasha Mustansar ◽  
Samuel A. McDonald ◽  
William Irvin Sellers ◽  
Phillip Lars Manning ◽  
Tristan Lowe ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Time Lapse ◽  
Image Correlation ◽  
Long Bone ◽  
Barnacle Goose ◽  
3D Images ◽  
X Ray ◽  
X Ray Computed

This paper uses X-ray computed tomography to track the mechanical response of a vertebrate (Barnacle goose) long bone subjected to an axial compressive load, which is increased gradually until failure. A loading rig was mounted in an X-ray computed tomography system so that a time-lapse sequence of three-dimensional (3D) images of the bone’s internal (cancellous or trabecular) structure could be recorded during loading. Five distinct types of deformation mechanism were observed in the cancellous part of the bone. These were (i) cracking, (ii) thinning (iii) tearing of cell walls and struts, (iv) notch formation, (v) necking and (vi) buckling. The results highlight that bone experiences brittle (notch formation and cracking), ductile (thinning, tearing and necking) and elastic (buckling) modes of deformation. Progressive deformation, leading to cracking was studied in detail using digital image correlation. The resulting strain maps were consistent with mechanisms occurring at a finer-length scale. This paper is the first to capture time-lapse 3D images of a whole long bone subject to loading until failure. The results serve as a unique reference for researchers interested in how bone responds to loading. For those using computer modelling, the study not only provides qualitative information for verification and validation of their simulations but also highlights that constitutive models for bone need to take into account a number of different deformation mechanisms.

scholarly journals Gold Exploration in Two and Three Dimensions: Improved and Correlative Insights from Microscopy and X-Ray Computed Tomography

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 476
Author(s):  
Joshua Chisambi ◽  
Bjorn von der Heyden ◽  
Muofhe Tshibalanganda ◽  
Stephan Le Roux
Keyword(s):  
Computed Tomography ◽  
Spatial Distribution ◽  
Gold Mineralization ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Low Grade ◽  
X Ray ◽  
3D Space ◽  
X Ray Computed ◽  
2D And 3D

In this contribution, we highlight a correlative approach in which three-dimensional structural/positional data are combined with two dimensional chemical and mineralogical data to understand a complex orogenic gold mineralization system; we use the Kirk Range (southern Malawi) as a case study. Three dimensional structures and semi-quantitative mineral distributions were evaluated using X-ray Computed Tomography (XCT) and this was augmented with textural, mineralogical and chemical imaging using Scanning Electron Microscopy (SEM) and optical microscopy as well as fire assay. Our results detail the utility of the correlative approach both for quantifying gold concentrations in core samples (which is often nuggety and may thus be misrepresented by quarter- or half-core assays), and for understanding the spatial distribution of gold and associated structures and microstructures in 3D space. This approach overlays complementary datasets from 2D and 3D analytical protocols, thereby allowing a better and more comprehensive understanding on the distribution and structures controlling gold mineralization. Combining 3D XCT analyses with conventional 2D microscopies derive the full value out of a given exploration drilling program and it provides an excellent tool for understanding gold mineralization. Understanding the spatial distribution of gold and associated structures and microstructures in 3D space holds vast potential for exploration practitioners, especially if the correlative approach can be automated and if the resultant spatially-constrained microstructural information can be fed directly into commercially available geological modelling software. The extra layers of information provided by using correlative 2D and 3D microscopies offer an exciting new tool to enhance and optimize mineral exploration workflows, given that modern exploration efforts are targeting increasingly complex and low-grade ore deposits.

Quantification of 3D macropore networks in forest soils in Touzhai valley (Yunnan, China) using X-ray computed tomography and image analysis

2017 ◽  
Vol 14 (3) ◽  
pp. 474-491 ◽  
Author(s):  
Jia-ming Zhang ◽  
Ze-min Xu ◽  
Feng Li ◽  
Ru-ji Hou ◽  
Zhe Ren
Keyword(s):  
Computed Tomography ◽  
Image Analysis ◽  
Forest Soils ◽  
X Ray ◽  
X Ray Computed

Visual analysis and X-ray computed tomography for assessing the spatial variability of soil structure in a cultivated Oxisol

2017 ◽  
Vol 173 ◽  
pp. 15-23 ◽  
Author(s):  
Carla E. Carducci ◽  
Yuri L. Zinn ◽  
Diogo F. Rossoni ◽  
Richard J. Heck ◽  
Geraldo C. Oliveira
Keyword(s):  
Computed Tomography ◽  
Spatial Variability ◽  
Soil Structure ◽  
Visual Analysis ◽  
X Ray ◽  
X Ray Computed

scholarly journals Assessment of the responses of soil pore properties to combined soil structure amendments using X-ray computed tomography

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yonghui Yang ◽  
Jicheng Wu ◽  
Shiwei Zhao ◽  
Qingyuan Han ◽  
Xiaoying Pan ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soil Structure ◽  
X Ray ◽  
X Ray Computed ◽  
Pore Properties

scholarly journals Understanding the mechanisms of root-reinforcement in soils: soil shear tests using X-ray computed tomography and digital volume correlation

2019 ◽  
Vol 92 ◽  
pp. 12009
Author(s):  
Daniel Bull ◽  
Ian Sinclair ◽  
Fabrice Pierron ◽  
Tiina Roose ◽  
Joel Smethurst
Keyword(s):  
Computed Tomography ◽  
Three Dimensions ◽  
Digital Volume Correlation ◽  
Strain Component ◽  
Multiscale Models ◽  
Root Reinforcement ◽  
Length Scales ◽  
X Ray ◽  
Shearing Resistance ◽  
X Ray Computed

Soil containing plant roots may be expected to exhibit a greater shearing resistance compared with the same ‘unreinforced’ soil, providing enhanced stability and effective erosion control, particularly for earth slopes. To be able to rely on the improved shearing resistance and stiffness of root-reinforced soils, it is important to understand and quantify the effectiveness of root reinforcement. This requires sophisticated multiscale models, building understanding at different length scales, from individual soil-root interaction through to full soil-profile or slope scale. One of the challenges with multiscale models is ensuring that they are representative of real behaviour, and this requires calibration to detailed high-quality experiments. The focus of the work presented was to capture and quantify root-reinforcement behaviour and associated soil and root deformation mechanisms during direct shear at the macroscopic to millimetre length scales. A novel shear box was developed to operate within a large-scale X-ray computed tomography (CT) scanner. Tests were interrupted to be scanned at a series of shear displacements from 0-20 mm to capture the chronology of behaviour in three-dimensions. Digital volume correlation (DVC) was applied to the CT dataset to obtain full-field 3D displacement and strain component information. The study demonstrates feasibility of the technique and presents preliminary DVC results.

Sign in / Sign up

Export Citation Format

Share Document