Mechanical size effect mechanisms in coral reef limestone based on digital rock core modeling
LI Xinping1, 2, 3, LI Wenhao1, 2, ZHOU Zhengrong2, 4, ZHU Yingwei1, 2, QU Dengxing2*, XIAO Wenxuan2, #br#
KUANG Linfeng2
(1. Sanya Science and Education Innovation Park, Wuhan University of Technology, Sanya, Hainan 572024, China; 2. School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, Hubei 430070, China; 3. Hainan Engineering Research Center for Construction and Protection of Islands and Reefs, Sanya, Hainan, 572024, China; 4. Sinohydro Bureau 9 Co., Ltd., Guiyang, Guizhou 550081, China)
Abstract：The highly heterogeneous three-dimensional pore network structure of coral reef limestone results in significant anisotropy and size effects on its mechanical properties. This research developed digital rock core models of coral reef limestone using CT scanning and adaptive threshold segmentation techniques, enabling the conversion between these digital models and finite element models through spatial mapping relationships. The mechanical response, damage evolution, and changes in porosity of coral reef limestone specimens of varying sizes under quasi-static compression were systematically investigated. The results indicate that: (1) As the model size increases, peak strength nonlinearly rises from 0.25 MPa to 7.26 MPa, with material behavior transitioning from ductile to brittle, and the post-peak response shifting from gradual strain softening to a sudden stress drop; (2) As specimen size increases, stress distribution evolves from highly concentrated patterns to more uniform distributions, ultimately developing into complex discrete multipolar states, with dominant stress directions becoming increasingly pronounced; (3) Larger models exhibit more complex fractal characteristics and progressive pore reconstruction processes, with significant nonlinear relationships observed between fractal dimension and porosity changes. This study elucidates the interaction mechanism between multi-scale pore structures and macroscopic geometric dimensions, providing a theoretical foundation for stability evaluation in island reef engineering.
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2026, Vol. 45 
