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| Study on the evolution law of tension fracture of diameter compression rock under internal driving force |
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Abstract Rock is a complex natural non-uniform brittle material. There is a big gap between tensile and compressive properties. Tensile failure often controls the overall stability of rock engineering. In this paper, the difference of internal forces acting on a certain point in rock within a certain scale is defined as internal driving force. Experiments on crack propagation of diametral compression rock are carried out. A high-speed camera was used to capture the transient tensile crack growth process and the first principal strain evolution process was analyzed by digital speckle software. The continuous-discontinuous method is used to simulate the tensile crack growth process of diametrically compressed rock. It can be seen from the experimental results that the crack propagation of tension fracture can be divided into three stages: the cumulative stage of tension fracture deformation (macro crack free), stable stage of tension fracture crack propagation and dynamic stage of tension fracture crack propagation. It compares the experimental and numerical results with the analytical solutions. The propagation law of experimental and numerical results is basically consistent, but different from the analytical solution of elasticity. The analytical solution is based on the assumption of homogeneity, while the external load and the rock itself are non-uniform. The external load and the inhomogeneity of the rock itself are the main reasons for the difference between the crack initiation point, propagation path and the analytical solution. Through comprehensive analysis, the law of tensile crack growth is given: the internal driving force is used to analyze the propagation law of tensile crack. When the internal driving force exceeds the connecting force of atom or molecule, the propagation direction is perpendicular to the direction of internal driving force. The study of crack propagation and evolution law of rock tension fracture can provide theoretical basis for the prevention and control of rock engineering tension failure.
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Received: 11 November 2022
Published: 18 April 2023
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2023, Vol. 44 
