Finite-discrete element modelling of fracture development in bimrocks

•FDEM is utilized to evaluate the failure of bimrocks under the influence of various parameters.•Block sizes, VBP, interface strength, and block shape are studied.•Failure patterns, mode, and load displacements are compared and discussed. Block-in-matrix rocks (bimrocks) are a complex geological fea...

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Veröffentlicht in:Engineering fracture mechanics 2024-09, Vol.308, p.110346, Article 110346
Hauptverfasser: Sharafisafa, Mansour, Aliabadian, Zeinab, Sato, Akira, Sainoki, Atsushi, Bahaaddini, Mojtaba, Kargar, Alireza, Reza Nejati, Hamid, Shen, Luming
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Sprache:eng
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Zusammenfassung:•FDEM is utilized to evaluate the failure of bimrocks under the influence of various parameters.•Block sizes, VBP, interface strength, and block shape are studied.•Failure patterns, mode, and load displacements are compared and discussed. Block-in-matrix rocks (bimrocks) are a complex geological feature composed of hard blocks in a weak matrix bonded together via a weak interface. The failure mechanism and deformation behavior of the bimrocks is quite complex due to the simultaneous existence of blocks with different shapes, strengths and proportions in a matrix. Therefore, it is of great importance to characterize the bimrocks under different situations. This study employs the combined finite-discrete element method (FDEM) to characterize the failure pattern and load carrying capacity of the bimrocks considering changes in various parameters, including block size, volumetric block proportion (VBP), the strength ratio of block-matrix interface to matrix, and the shape of the blocks (angular, circular, and elliptical shapes). First, the robustness and feasibility of the FDEM in modeling fracture development is verified against an analytical solution as well as a series of experimental tests accompanied with the digital image correlation (DIC) method. Then, the verified model is used to model disc specimens with various block shapes and properties. The results indicate the remarkable influence of VBP, block size and block-matrix interface characteristics on the bimrock mechanical behavior under the same VBP. The results are assessed based on macroscopic observations to investigate the influence of determinative physical properties of bimrocks. The results are also evaluated based on the mode of failure, mode I, II, or mixed mode, to qualitatively elucidate the influence of key factors on the formation of different cracks in different places, including the interface of matrix-blocks or intergrain or intragrain. The results show that since the loading is a quasi-static scheme, all the cracks are intergrain and no intragrain crack is observed for any VBP. The simulations outcomes shows that the block sizes determine the failure pattern, failure mode, and load–displacement behavior, where the larger blocks exhibiting the lowest load carrying capacity due to experiencing more interface breakage in shear. It is found that the VBP is a crucial parameter in the deformation of the bimrocks, showing that the strength of the bimrocks significantly increases with a decr
ISSN:0013-7944
DOI:10.1016/j.engfracmech.2024.110346