Investigation of Microcrack Propagation and Energy Evolution in Brittle Rocks Based on the Voronoi Model |
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Authors: | Guanlin Liu Youliang Chen Xi Du Peng Xiao Shaoming Liao Rafig Azzam |
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Institution: | 1.Department of Civil Engineering, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China; (G.L.); (X.D.); (P.X.);2.Department of Engineering Geology and Hydrogeology, RWTH-Aachen University, 52064 Aachen, Germany;3.School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia;4.Department of Geotechnical Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China; |
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Abstract: | The cracking of rock mass under compression is the main factor causing structural failure. Therefore, it is very crucial to establish a rock damage evolution model to investigate the crack development process and reveal the failure and instability mechanism of rock under load. In this study, four different strength types of rock samples from hard to weak were selected, and the Voronoi method was used to perform and analyze uniaxial compression tests and the fracture process. The change characteristics of the number, angle, and length of cracks in the process of rock failure and instability were obtained. Three laws of crack development, damage evolution, and energy evolution were analyzed. The main conclusions are as follows. (1) The rock’s initial damage is mainly caused by tensile cracks, and the rapid growth of shear cracks after exceeding the damage threshold indicates that the rock is about to be a failure. The development of micro-cracks is mainly concentrated on the diagonal of the rock sample and gradually expands to the middle along the two ends of the diagonal. (2) The identification point of failure precursor information in Acoustic Emission (AE) can effectively provide a safety warning for the development of rock fracture. (3) The uniaxial compression damage constitutive equation of the rock sample with the crack length as the parameter is established, which can better reflect the damage evolution characteristics of the rock sample. (4) Tensile crack requires low energy consumption and energy dispersion is not concentrated. The damage is not apparent. Shear cracks are concentrated and consume a large amount of energy, resulting in strong damage and making it easy to form macro-cracks. |
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Keywords: | rock failure crack development fracture mechanism Voronoi model energy evolution |
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