Microstructure effect of mechanical and cracking behaviors on brittle rocks using image-based fast Fourier transform method  

作　　者：Mingyao Li Lei Peng Dejun Liu Jianping Zuo 

机构地区：[1]School of Mechanics and Civil Engineering,China University of Mining and Technology,Beijing,100083,China [2]State Key Laboratory for Tunnel Engineering,China University of Mining and Technology,Beijing,100083,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2025年第1期399-413,共15页岩石力学与岩土工程学报(英文)

基　　金：supported by the National Natural Science Foundation of China(Grant No.11802332);the China Scholarship Council(Grant No.202206435003);the Fundamental Research Funds for the Central Universities(Grant No.2024ZKPYLJ03).

摘　　要：The internal microstructures of rock materials, including mineral heterogeneity and intrinsic microdefects, exert a significant influence on their nonlinear mechanical and cracking behaviors. It is of great significance to accurately characterize the actual microstructures and their influence on stress and damage evolution inside the rocks. In this study, an image-based fast Fourier transform (FFT) method is developed for reconstructing the actual rock microstructures by combining it with the digital image processing (DIP) technique. A series of experimental investigations were conducted to acquire information regarding the actual microstructure and the mechanical properties. Based on these experimental evidences, the processed microstructure information, in conjunction with the proposed micromechanical model, is incorporated into the numerical calculation. The proposed image-based FFT method was firstly validated through uniaxial compression tests. Subsequently, it was employed to predict and analyze the influence of microstructure on macroscopic mechanical behaviors, local stress distribution and the internal crack evolution process in brittle rocks. The distribution of feldspar is considerably more heterogeneous and scattered than that of quartz, which results in a greater propensity for the formation of cracks in feldspar. It is observed that initial cracks and new cracks, including intragranular and boundary ones, ultimately coalesce and connect as the primary through cracks, which are predominantly distributed along the boundary of the feldspar. This phenomenon is also predicted by the proposed numerical method. The results indicate that the proposed numerical method provides an effective approach for analyzing, understanding and predicting the nonlinear mechanical and cracking behaviors of brittle rocks by taking into account the actual microstructure characteristics.

关 键 词：Rock microstructure Cracking process Brittle rocks Fast Fourier transform(FFT) Digital image processing(DIP) 

分 类 号：TU452[建筑科学—岩土工程]