A rock compression fracture prediction method

Abstract

The invention belongs to the field of rock fracture prediction, and relates to a rock compression fracture prediction method. Equipment required in the method includes a universal tester, a universal test control system, a CCD industrial camera and a computer. The method includes firstly debugging the CCD industrial camera and the universal tester, then putting a sand rock test piece at the center position of the universal tester, allowing the surface sprayed with speckles of the sand rock test piece to face the CCD industrial camera, shooting an image in the bmp format as an original reference image before deformation, storing the image in the computer as an initial comparison image for later use, then collecting images in a process in which the sand rock test piece is compressed by the universal tester, adopting the collected images as sequential target images after deformation, and subjecting the initial image and the target images after deformation to comparison analysis by utilizing a digital image correlation process to obtain displacement and strain information of the images after deformation relative to the image before deformation. The method is ingenious in design conception, simple to operate, accurate in measurement result, friendly in application environment and wide in market prospect.

Description

Technical field: [0001] The invention belongs to the field of rock failure prediction, and relates to a rock compression failure prediction method, which obtains the full-field strain from the digital image correlation method, selects typical points as research objects, discusses the strain change law before and after the failure of the typical points, and finds the failure method. The strain threshold of , so as to realize the prediction of rock failure. Background technique: [0002] Traditional mechanical research usually assumes that the material is continuous and uniform, without considering the defects or cracks of the material itself, but cracks can be seen everywhere in the underground rock mass, and the existence of cracks greatly reduces the macroscopic stiffness of the rock mass, which makes the deformation of the bunker aggravated. lead to engineering accidents. In the prior art, most scholars focus on theoretical analysis when studying rock failure, and propose...

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Problems solved by technology

[0002] Traditional mechanical research usually assumes that the material is continuous and uniform, without considering the defects or cracks of the material itself, but cracks can be seen everywhere in the underground rock mass, and the existence of cracks greatly reduces the macroscopic stiffness of the rock mass, which makes the deformation of the bunker aggravated. lead to engineering accidents

In the prior art, most scholars focus on theoretical analysis when studying rock failure, and propose various rock strength criteria and correction methods, including the earliest and most widely used Mohr-Coulomb criterion. However, due to the complexity and randomness of rock However, these methods generally have defects, and there are no good solutions to many problems

Later, some scholars improved and revised the above methods, and some scholars proposed a unified strength theory, but no theory can fully describe the rock failure mechanism; some scholars used numerical simulation methods to study rock failure, Chen Xin et al. Yuan software for simulation calculation and crack initiation mechanism analysis; Hu Mingyan used ABAQUS finite element software to conduct numerical simulation research on layered composite rocks, but most of them have certain theoretical support, and the numerical models are for the purpose of verifying feasibility

[0003] Studying rocks through experiments can obtain effective data most directly. With the continuous improvement of research methods, the research on rocks is also deepening. Zhou Huoming and others use CT to study rocks, but CT is difficult to achieve in ordinary laboratories, which also limits Compared with other methods, the digital image correlation method has the advantages of non-contact measurement of the whole field strain, so it is widely used in rock research, but the traditional compression test can only get the stress-strain before rock failure The relationship curve and its peak strength, which are far from meeting the requirements for the development of rock engineering and the in-depth study of rock mechanical properties, so the present invention designs a method for predicting rock failure, and obtains the full range of rock from the digital image correlation method. Field strain, discuss the strain change law before and after failure of typical points, and find the failure strain threshold, so as to realize rock failure prediction

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