On the Mechanical Behavior of Granite Material With Particular Emphasis on the Influence From Pre-Existing Cracks and Defects

• Published in: Journal of testing and evaluation 2018-01, Vol.46 (1), p.33-45
• Main Authors: Saadati, M., Forquin, P., Weddfelt, K., Larsson, P. L., Hild, F.
• Format: Article
• Language: English
• Subjects: constitutive characterization; digital image correlation (DIC); granite; Mechanics; Mechanics of materials; Physics; pre-existing cracks; quasi-oedometric; three-point bending
• ISSN: 0090-3973; 1945-7553; 1945-7553
• DOI: 10.1520/JTE20160072

In this investigation, experiments were carried out in order to determine the mechanical properties of Bohus granite considering the influence from pre-existing cracks and defects. The experimental investigation aimed at a complete material characterization, for the purpose of mechanical analyses using advanced constitutive models, based on a variety of tests. In doing so, direct tensile and compression tests were performed to evaluate the stiffness and strength; quasi-oedometric tests were carried out in order to obtain the deviatoric and volumetric behavior of the material at different levels of hydrostatic pressure (up to 860 MPa); three-point bend tests were performed to evaluate the quasi-static strength of the rock and its distribution. Weibull statistics was then employed to describe the strength distribution. The intact specimens indicated a rather low scatter in the mechanical properties such as Young’s modulus and tensile strength. However, specimens with large initial defects behaved differently. The failure mechanism in these specimens was not as brittle as the intact ones. The crack was opened on the tensile surface of such specimens during the three-point bend test at an early stage during loading, as demonstrated by digital image correlation results.