CT-Based Pore Network Characterization of Coral Reef Rudstone and Its Correlation with Physico-Mechanical Properties

Coral reef rudstone (CRR) exhibits distinctive fabric-controlled mechanical behavior that is strongly influenced by its internal pore structure and degree of diagenesis. This study combines petrographic observation, X-ray CT scanning, and saturated uniaxial compression testing to quantify the pore network characteristics and physico-mechanical properties of CRR. Three representative specimens were reconstructed in three dimensions and analyzed in terms of pore number, pore volume, throat length, and coordination number. The results show that CRR contains moderately developed pores dominated by micritic-calcite dissolution pores. Average pore radius ranges from 141.2 to 993.6 μm, the maximum pore radius reaches 5567.2 μm, and the throats are mainly short-range, with average lengths of 3705–5437 μm. Connectivity varies markedly among specimens: CRR-C contains an interconnected macropore cluster, whereas CRR-A and CRR-B are dominated by weakly connected mesopores. Dry density shows a strong nonlinear positive correlation with saturated uniaxial compressive strength, whereas porosity shows a negative correlation. Both variables exhibit preliminary exponential relationships with strength and constitute key controls on the mechanical response of CRR.