Dependence of Macro Mechanical Behaviour of Gypsum Rock on Micro-scale Grain-Size Distribution. Issue 2 (12th April 2019)

• Record Type: Journal Article
• Authors: Caselle, C.; Bonetto, S.; Vagnon, F.; Costanzo, D.
• Is Part Of: Géotechnique letters. Volume 9:Issue 2(2019)
• Page Start: 1
• Page End: 23
• Publication Date: 2019-04-12
• Subjects: Rock Mechanics -- Fabric -- Soft Rocks; Geotechnical engineering -- Periodicals; Engineering geology -- Periodicals; 624.151
• DOI: 10.1680/jgele.18.00206
• Languages: English
• ISSNs: 2045-2543

Abstract

Abstract : The exploitation of gypsum by both open pit and underground quarries requires attentive evaluations of mechanical features and variability. However, gypsum rock testing often neglects the natural heterogeneity. The result is an inaccurate mechanical characterization that averages the strength values of different materials leading to an underestimation or the overestimation of the stability conditions, without offering a real representation of the mechanical behaviour of the rock. Grain-size, grain-sorting, mineral composition and porosity significantly influence gypsum mechanical behaviour. The individuation of textural and compositional features that primarily influence the variation in mechanical parameters may offer an interpretation key of the phenomenon. In this study, the relation between features at the microscale and macro-mechanical behaviour of gypsum rock was analysed with a multiscale approach. Relationships between Uniaxial Compression Strength (UCS), grain-size distribution and porosity were analysed and discussed. Microscopic observations on thin sections were performed, developing an image analysis procedure for correlating textural and structural parameters with UCS.