Numerical modelling of the crack-pore interaction and damage evolution behaviour of rocklike materials with pre-existing cracks and pores

Abstract

The combined effect of pre-existing cracks and pores on the damage evolution behaviour and mechanical properties of rocklike materials under uniaxial compression was numerically studied. Simulations of cracks and pores alone showed that increasing crack length and pore diameter decrease uniaxial compressive strength (UCS) and elastic modulus. Subsequent simulations considered two types of combinations of pre-existing cracks and pores – two cracks either side of a centric pore, and two pores either side of a centric crack – and the distance between cracks and pores was changed. In the case of two cracks at either side of the pore, UCS increased only slightly when the distance between the cracks and pore was increased. This was attributed to the more profound effect of the presence of the pore on UCS, and was confirmed by the progressive crack development characteristics and the major principal stress distribution patterns, which showed that the cracks initiated from the tips of the two pre-existing cracks made little or no contribution to the ultimate macroscopic failure. In contrast, models with two pores at either side of a centric crack showed a marked dependency of UCS on the distance between the pores and the crack. Cracks propagating from pre-existing pores made a greater contribution to the ultimate macroscopic failure when the pores were close to the centric crack and the effect gradually diminished with increasing space between pre-existing pores and the centric crack. Major principal stress distributions showed an asymmetric mobilisation of compressive stresses at the right and left sides of the two pores, favouring macroscopic shear failure when they were close to the centric crack which had led to a lower UCS. Overall, this study presents some critical insights into crack-pore interaction behaviour and the resulting mechanical response of rocklike materials to assist with the design of rock structures.

Experimental investigation on dynamic mechanical properties and fracture evolution behavior of the underground openings with excavation damaged zones

“…In EDZ, the physical and mechanical properties of rock mass, including strength, moduli, stiffness, etc., are obviously reduced. Under the action of external force, the damaged rock mass is further deformed and destroyed, and the initial damaged area is also considered to be the starting point of the later damage evolution (Bai et al., 2020; Munoz and Taheri, 2017; Wasantha et al., 2020; Wong and Peng, 2020; Xu et al., 2004). Similarly, in contrast with intact rock, the mechanical properties of holed rock have the same variation characteristics, and the starting position of damage accumulation under external force is generally in the vicinity of the hole because of stress concentration (Fakhimiet al, 2002; Li et al., 2020; Zhao et al., 2020; Zhu et al., 2021).…”

Impact of Stress-Induced Rock Damage on Elastic Symmetry: From Transverse Isotropy to Orthotropy

“…To date there have been many numerical and experimental studies on the influence of single or multiple flaws, pores and joints localised at the macroscale level on the mechanical behaviour of isotropic rocks loaded under either uniaxial or triaxial conditions (Mondal et al 2019(Mondal et al , 2020aGriffiths et al 2017;Wasantha et al 2021;Tang and Kou 1998;Xue et al 2021;Xu et al 2013). We extend this analysis to consider the influence of bedding planes of initially transverse isotropic rocks and its orientation with respect to the uniaxial stress applied.…”

Mixed-modes (I/III) fracture of aluminum foam based on micromechanics of damage

“…These methods consist of real-based multi-scale damage detection for modeling and evaluation (Saramito et al., 2021; Shamsirband and Khansari, 2021). The influences of a two dimensional pore-like flaw (Bristow, 1960; Wasantha et al., 2020; Wong and Peng, 2020) and three dimensional porous (Lee and Ju, 2008) on mechanical properties and fracture prediction of brittle materials were investigated with respect to various loading conditions. Not only size and location of porous, but also interactions of randomly located pore-like cracks were studied based on different material properties (Li et al., 2017; Theocaris, 1998; Wasantha et al., 2020).…”