Estimation of the mode I fracture toughness and evaluations on the strain behaviors of the compacted mine tailings from full-field displacement fields via digital image correlation

Abstract

Ore beneficiation processes produce huge quantities of waste rock in the form of tailings. For dispersed remote artisanal mining sites that are unapproachable to strong construction and building materials, compacted MTs can be utilized an alternative to construct civilian buildings. The mechanical behaviors of compacted clay and adobe masonry were studied by numerous researchers; however, the understanding of the strain behavior and fracture properties was insufficient to illustrate compacted MTs due to differences in the material properties. Therefore, in this paper, the strain behavior and fracture properties of compacted MTs under mode I loading condition were explored. A series of semi-circular bending (SCB) tests were performed to examine the mode I fracture behavior of compacted MTs at different notch depths. Simultaneously, digital image correlation (DIC) technique was utilized to acquire the surface image sequence under mode I loading condition in order to characterize the strain behaviors. Williams series was introduced to measure the mode I fracture toughness in a full-field displacement field via DIC analysis. The mode I fracture toughness obtained by empirical equation, the Williams series, and the modified empirical equation considering plasticity in the notch tip were all comparatively examined in this paper. Moreover, the strain behaviors of the compacted MTs at different loading levels were explored. Finally, the size of the fracture process zone (FPZ) and crack tip opening displacement (CTOD) were quantified by using DIC. Results revealed that the mode I fracture toughness obtained from full-field displacement field and modified empirical equation analysis was larger than from the empirical equation.