Rock mass mesoscopic fracture testing method based on three-dimensional digital speckles

Abstract

The invention relates to the technical field of rock mass deformation measurement, in particular to a rock mass mesoscopic fracture testing method based on three-dimensional digital speckles. The method comprises the following steps: building a discrete physical model according to the working face geological conditions of a to-be-researched object; manufacturing speckles on the surface of the model, and keeping the shooting direction of a digital camera device perpendicular to the model; and collecting model images under different advancing distances by using the digital camera device, processing the images through an image processing device, and acquiring displacement and strain values of different measuring line positions under different advancing distances to realize microcosmic fracture positioning and fracture opening degree and fracture development length determination. According to the rock mass mesoscopic fracture testing method, the generation and development of the mesoscopicfractures of the overlying strata can be quantitatively described, the mesoscopic fractures can be effectively detected, high measurement precision can be realized, rock deformation is visualized into a mesoscopic scale, and effective technical and data support is provided for research of rock mass failure rules, rock stratum development rules and the like.

Description

technical field [0001] The invention relates to the technical field of rock mass deformation measurement, in particular to a method for testing rock mass mesoscopic cracks based on three-dimensional digital speckle. Background technique [0002] The occurrence and development law and quantitative description of fracture network in mined rock mass is one of the basic and difficult problems in today's mine rock mass mechanics. The similar model test can well reproduce the formation process and distribution state of stope rock mass cracks in the laboratory. Due to its short test period, reliable results, and intuitive test results, it is widely used in technical issues related to mining engineering. [0003] 3D digital speckle technology is an optical method based on non-contact images. First, digital imaging equipment is used to acquire digital images of objects under different loads, and then image analysis is performed using correlation-based matching algorithms to quantitat...

AI Technical Summary

Problems solved by technology

[0004] For the extraction and quantification of fracture development and fracture shape information in the process of simulation advancement of similar material models, at present, digital cameras are used to collect fracture evolution maps during the mining process, and digital image processing techniques such as manual sketching or image binarization are used for description. and expression; however, the binarization method will affect the analysis and processing of the image, and sometimes some image details may be lost, and the extraction of mesostructure and morphological information is prone to deviation

Other processing methods, such as using the surface scanning system to obtain the point cloud data of the model surface, and then extract the model rupture boundary to obtain the crack development information; rasterize the 3D point cloud data of the similar model surface to generate a composite image, according to the point cloud and pixel Based on the mapping relationship to obtain fracture development information; based on visual measurement combined with marker point positioning to extract model fracture development information, etc., these methods have low detection efficiency, high observation costs, and poor extraction of small fractures that are not easy to identify

In summary, the current methods for detecting mesoscopic cracks in rock mass with similar material models are lacking.

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