Observing strain localisation processes in bio-cemented sand using x-ray imaging

Tagliaferri, Francesco; Waller, Jack; Andò, Edward; Hall, Stephen A.; Viggiani, Gioacchino; Bésuelle, Pierre; DeJong, Jason T.

doi:10.1007/s10035-011-0257-4

Cited by 70 publications

(17 citation statements)

References 4 publications

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“…Experimental work on real sands has been limited. Cross sections of epoxy-hardened sand specimens have been investigated microscopically [12,18,25], and more recently, micro-X-ray Computed Tomography (lCT) has been used, e.g., [15,40]. Both techniques allow for very detailed particle contact maps.…”

Section: Introductionmentioning

confidence: 99%

Characterization of mesoscale instabilities in localized granular shear using digital image correlation

Rechenmacher

Abedi

Chupin³

et al. 2011

Acta Geotech.

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Within shear bands in sands, deformation is largely non-affine, stemming primarily from buckling of well-known force chains and also from vortex-like structures. In the spirit of current trends toward multiscale modeling, understanding the links between these mesoscale deformational entities and corresponding macroscale response will form the basis for the next generation of sand behavioral models and may also aid in efforts to understand jamming-unjamming transitions in dense granular flows in general. Experimental methods to quantify and characterize such subscale kinematics, in particular in real sands, will play critical roles in these efforts. Digital Image Correlation (DIC) is a fast growing experimental technique to nondestructively measure surface displacements from digital images. Here, DIC has been employed to identify and characterize the development of vortex structures inside shear bands formed in dense sands during plane strain compression. A rigorous assessment of the DIC method has been performed, in particular for subscale behavioral characterization in unbonded granular solids, and guidelines are offered for accurate implementation. While DIC systematically overestimates shear band thickness, a methodology has been devised to compensate for this overestimation. Shear band thickness for four different uniform sands were found to range between 6 and 9 grain diameters, and for a well-graded sand between 8 and 9.5 grain diameters. These determinations agree with visual inspections of grain kinematics from the image data, as well as recent theoretical predictions.

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Section: Introductionmentioning

confidence: 99%

Characterization of mesoscale instabilities in localized granular shear using digital image correlation

Rechenmacher

Abedi

Chupin³

et al. 2011

Acta Geotech.

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“…Laboratory-scale element tests have shown substantial (. 10 3 3) increases in strength (DeJong et al, 2006;Whiffin et al, 2007;Van Paassen et al, 2009;Chu et al, 2011Chu et al, , 2013Al Qabany & Soga, 2013), decreases in hydraulic conductivity greater than two orders of magnitude Rusu et al, 2011;Martinez et al, 2013), increases in small-strain stiffness by three orders of magnitude (DeJong et al, 2006;Van Paassen et al, 2010b;Van Paassen, 2011;Esnault-Filet et al, 2012), and an increase in dilative tendencies (Chou et al, 2011;Tagliaferri et al, 2011). Even after cementation degrades owing to shearing, the reduction in pore space (or increase in solids density) due to the precipitated calcite alters the behaviour of the material.…”

Section: Microbially Induced Calcite Precipitationmentioning

confidence: 99%

Biogeochemical processes and geotechnical applications: progress, opportunities and challenges

DeJong¹,

Soga²,

Kavazanjian³

et al. 2014

Bio- And Chemo-Mechanical Processes in Geotechnical Engineering

116

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Consideration of soil as a living ecosystem offers the potential for innovative and sustainable solutions to geotechnical problems. This is a new paradigm for many in geotechnical engineering. Realising the potential of this paradigm requires a multidisciplinary approach that embraces biology and geochemistry to develop techniques for beneficial ground modification. This paper assesses the progress, opportunities, and challenges in this emerging field. Biomediated geochemical processes, which consist of a geochemical reaction regulated by subsurface microbiology, currently being explored include mineral precipitation, gas generation, biofilm formation and biopolymer generation. For each of these processes, subsurface microbial processes are employed to create an environment conducive to the desired geochemical reactions among the minerals, organic matter, pore fluids, and gases that constitute soil. Geotechnical applications currently being explored include cementation of sands to enhance bearing capacity and liquefaction resistance, sequestration of carbon, soil erosion control, groundwater flow control, and remediation of soil and groundwater impacted by metals and radionuclides. Challenges in biomediated ground modification include upscaling processes from the laboratory to the field, in situ monitoring of reactions, reaction products and properties, developing integrated biogeochemical and geotechnical models, management of treatment by-products, establishing the durability and longevity/reversibility of the process, and education of engineers and researchers.

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“…This is known as Digital Image Correlation (DIC) which is a technique that maps an image onto another. This method has gained popularity in characterisation of kinematics of evolving structures for its ability to measure bulk deformation and strain fields as well as volumetric strain changes [14,15,14]. We implement a discrete DIC (D-DIC) based on tracking of each grain throughout the compaction process at imaging intervals S0-S1, S1-S2, S2-S3 and S3-S4.…”

Section: Particle Tracking and Delaunay-based Digital Image Correlationmentioning

confidence: 99%

Grain-based characterisation and acoustic wave propagation in a sand packing subject to triaxial compression

Saadatfar¹,

Nicolas²,

Arad³

et al. 2013

AIP Conference Proceedings

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Abstract. This paper presents a study of 3D deformation process in a dry packing of Ottawa sand. X-ray microtomography is used to acquire scans of a triaxial test of the sample at five axial stress levels. Using 3D image analysis we are able to resolve particle scale features. Particle tracking combined with finite element simulations reveal that the rotational transformation of particles is one of the primary mechanisms of elastic energy dissipation at the grain scale. By analysing grain contact orientation, we show that stress induced anisotropy is spatially correlated to the compressional elastic wave.

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Observing strain localisation processes in bio-cemented sand using x-ray imaging

Cited by 70 publications

References 4 publications

Characterization of mesoscale instabilities in localized granular shear using digital image correlation

Characterization of mesoscale instabilities in localized granular shear using digital image correlation

Biogeochemical processes and geotechnical applications: progress, opportunities and challenges

Grain-based characterisation and acoustic wave propagation in a sand packing subject to triaxial compression

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