深层珊瑚礁灰岩作为岛礁工程的主要承载介质,其内部发育的多尺度孔隙是引发岩体强度衰减和损伤区破坏特征难以预测的关键因素。本文基于高精度CT扫描和数字图像分析技术,对格架型、砾块型、砾屑型与砂屑型四类典型的深层珊瑚礁灰岩进行三维结构重构与参数化分析。结果表明,孔隙体积、表面积、形状因子与长轴等参数均呈右偏分布,指示小尺寸孔隙分布频率高,而介观-宏观孔隙分布频率低但力学影响显著。孔隙的3条主轴长度间表现为高度正相关,表明侵蚀和溶蚀等成岩过程对孔隙的塑造具有等比例缩放的特性。基于孔隙扰动应力场的叠加准则,构建了一种同时考虑应力衰减与孔隙尺度效应的复杂网络模型,并以加权度与中介中心度识别对力学性能起控制作用的关键孔隙,研究成果可为深层珊瑚礁灰岩力学劣化机理研究提供新的见解。

Deep coral reef limestone, as the primary load-bearing medium in island-reef engineering, contains multi-scale pores whose internal development is a key factor causing strength degradation and making the failure characteristics of damaged zones difficult to predict. Based on high-resolution CT scanning and digital image analysis techniques, this study conducted three-dimensional structural reconstruction and parametric analysis of four typical structural types of deep coral reef limestone, namely framework, boulder, gravel, and calcarenite. The results show that pore volume, surface area, shape factor, and major axis length all exhibit right-skewed distributions, indicating a high frequency of small-sized pores, whereas meso- to macro-scale pores occur less frequently but exert a significant mechanical influence. The lengths of the three principal pore axes are highly positively correlated, suggesting that diagenetic processes such as erosion and dissolution shape pores through proportional enlargement or reduction. Based on the superposition criterion of pore-perturbed stress fields, a complex network model was established that simultaneously considers stress attenuation and pore size effects. Weighted degree and betweenness centrality were then used to identify the key pores controlling the mechanical properties, providing insights into the mechanism of mechanical deterioration in deep coral reef limestone.