From rock microstructure to macromechanical properties based on fractal dimensions

Dongmei Huang,Yanchun Yin,Xikun Chang,Kai Fang,Yunliang Tan

doi:10.1177/1687814019836363

Dongmei Huang, Yanchun Yin + Show 3 more

Open Access

https://doi.org/10.1177/1687814019836363

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Abstract

Basic rock mechanical parameters, that is, the uniaxial compressive strength σc and elastic modulus E, have close relationships with the fractal dimension and inhomogeneity. Scanning electronic microscopy and fractal dimension calculations are applied to four different rock types (mudstone, sandstone, limestone, and basalt) in order to investigate the relationships between the rock mechanical properties, fractal dimensions, and homogeneity. The results show that the fractal dimension of each rock type fluctuates as the scanning electronic microscopy magnification increases. Rocks with different uniaxial compressive strength and elastic modulus values possess different self-similarity properties, and when the uniaxial compressive strength or elastic modulus increases, the fractal dimension of the rock microstructure decreases. The rock homogeneity is consistent with the fractal dimension, that is, the higher the homogeneity is, the larger the fractal dimension. Generally, homogeneity refers to the macroscale, and fractal dimension refers to the microscale. Overall, this research provides an innovative and effective approach for researching the mechanical behavior of rocks through a combination of uniaxial compression tests, homogeneity, and fractal dimensions.

Highlights

It is generally acknowledged that rock mechanical properties are greatly influenced by rock microscopic characteristics.[1]
The study of the fractal characteristics that are calculated from scanning electronic microscopy (SEM) imagery is an excellent method for understanding microscopic rock deformation mechanisms
The results show that the CC and fractal dimension have similar variations with increasing magnification, thereby demonstrating that the magnification has an important influence on the self-similarity of the rock structures

Summary

Introduction

It is generally acknowledged that rock mechanical properties are greatly influenced by rock microscopic characteristics.[1]. The four typical rock types, that is, sandstone, mudstone, limestone, and basalt, are examined using uniaxial compression testing. The boxcounting approach is adopted to calculate the fractal dimensions of rock microstructures.[32] The SEM images are processed into binary images using MATLAB.

Results

Conclusion