Evolution of Local Strains Under Uniaxial Compression in an Anisotropic Gypsum Sample

Caselle, Chiara; Umili, Gessica; Bonetto, Sabrina Maria Rita; Costanzo, Daniele; Ferrero, Anna María

doi:10.1007/978-3-030-21359-6_48

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…The DIC technique compares a series of digital images, for example, of the surface of a loaded specimen, and measures the displacements by matching the same pixels in consecutive photographs, before and after deformation. This technique, used in many research fields, has been widely and successfully employed in rock mechanics [51][52][53].…”

Section: Gradementioning

confidence: 99%

Preliminary Characterisation of an Italian Soft Rock with a Block-in-Matrix Fabric

et al. 2022

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Mélanges are heterogeneous geological deposits and represent the most widespread bimrock (block-in-matrix) formations. This paper presents the efforts undertaken to characterise an Italian mélange composed of a clayey-marly matrix enclosing strong calcareous blocks. Due to its low uniaxial compressive strength, this geomaterial can be classified as a soft rock. The weak nature of the marly matrix and its water sensitivity, as well as the presence of rock inclusions, made the collection and preparation of intact specimens extremely complex and time-consuming operations. The difficulties encountered during these phases are described in detail; the various non-conventional procedures considered and developed to overcome these problems are also presented. The potential of the solutions proposed lies in the fact that they can be conveniently applied to other soft rocks with a block-in-matrix internal arrangement, such as the Italian mélange. To characterise the Italian mélange, point load and uniaxial compressive tests were carried out. From the results of these tests, a conversion factor equal to 14 is proposed to correct the point load strength index in order to estimate the uniaxial compressive strength of soft rocks, such as the mélange under study. Moreover, to estimate local strains and the deformability of the geomaterial, the non-destructive digital image correlation technique was applied.

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Section: Gradementioning

confidence: 99%

Preliminary Characterisation of an Italian Soft Rock with a Block-in-Matrix Fabric

et al. 2022

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“…The microstructural mechanisms that control the strain accommodation in gypsum have for long time interested the scientific world and are still not completely understood [12][13][14]. The coalescence of cracks in synthetic and natural gypsum samples have been successfully investigated by means of the visual analysis and comparison of photographic sequences [15][16][17][18][19]. However, this methodology cannot be directly applied to more complex loading conditions, when the sample is inserted in a visual opaque structure for the application of a confining pressure.…”

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confidence: 99%

Crack coalescence and strain accommodation in gypsum rock

Caselle

Bonetto

Costanzo

2020

Frattura Ed Integrità Strutturale

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The micro-mechanisms involved in the deformation of gypsum rock have for long time interested the scientific world and are still not completely understood. The present work proposes an experimental investigation of strain accommodation in gypsum rock, reporting data referred to uniaxial and triaxial stress conditions. The rock deformation was investigated with a multiscale approach, with the comparison of results from DIC and microstructural analyses, aiming to propose an interpretation of crack coalescence and strain accommodation in natural gypsum rock (i.e. branching selenite facies), focusing on the influence of textural and compositional layering on the mechanical response. The failure was observed to coalesce following an unstable step-wise process. With the increase of confining pressure, the material develops a structure of plastic accommodation of strain, favoured by the peculiar crystallographic structure of gypsum, with water molecules layered in the salt structure.

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