Rock type-I crack expansion whole process detection method based on three-point bending test

Abstract

The invention discloses a rock type-I crack expansion whole process detection method based on three-point bending tests. The rock type-I crack expansion whole process detection method comprises the following steps: prefabricating a type-I crack in the middle part of a three-point bending test piece, performing jetting speckling treatment in an appointed analysis area of the test piece, and performing three-point bending tests on the appointed analysis area; meanwhile, performing whole process continuous imaging on the appointed analysis area, acquiring digital images, and analyzing, so as to obtain horizontal tension strain epsilon h of the whole test process of the appointed analysis area of the three-point bending test piece; coring the three-point bending test piece after the tests, manufacturing a Brazilian split disc test sample, performing sharp Brazilian split disc tests on the Brazilian split disc test sample so as to obtain ultimate tensile strain epsilon T, and comparing different values of epsilon h so as to obtain time nodes that horizontal tensile strain in different positions meets the ultimate tensile strain epsilon T in the whole type-I crack expansion process of the three-point bending test piece; according to second strength principles, acquiring crack expansion whole process information of type-I cracks of rock under the action of three-point bending. The rock type-I crack expansion whole process detection method disclosed by the invention is simple and easy to operate and precise in test result.

Description

technical field [0001] The invention relates to a rock fracture mechanics test method, in particular to a method for detecting the whole process of rock type I crack propagation based on a three-point bending test. Background technique [0002] Regarding the research on the expansion process of rock cracks, it is more common at present to use high-speed cameras for continuous shooting, and then obtain relatively qualitative results. With the development of computer software, non-contact measurement has gradually become popular, and the most effective one should be the digital photographic strain field measurement technology based on the principle of digital speckle correlation method (DSCM). Digital photography deformation field measurement can be understood as a modern measurement technology that uses image acquisition equipment such as high-definition digital cameras to first take pictures of the observation target, and then uses digital image analysis software to perform ...

AI Technical Summary

Problems solved by technology

This method can realize dynamic and high-speed acquisition, but due to the complexity of the crack growth process, the digital photography measurement method can only obtain the evolution characteristics of the strain field near the crack, but cannot quantitatively judge the macroscopic crack initiation of the crack and obtain the whole process of crack growth Information

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