Study on dynamic response characteristics of reef limestone under underwater explosion and evolutionary patterns of carbon emissions

• Reduced detonation depth, increased distance, and lower water depth mitigate rock mass dynamic disturbance. • Higher charge boosts response but shows nonlinear imbalance in efficiency-carbon gains. • KMO-PCA identifies velocity as core regulatory factor for dynamic response. • Carbon-score clustering validates the criticality of blasting parameter optimization. • Carbon emissions formula derived from Sadovsky formula and emissions accounting model. In response to the threats posed by underwater explosions to the stability of island-reef engineering structures and coral reef ecosystems, this study investigates the dynamic response characteristics and carbon emission evolutionary patterns of reef limestone under underwater explosion loads through a multi-parameter coupling analysis method. Based on an equivalent model, 11 test cases were designed to analyze the time-history evolution characteristics of shock waves, velocity, and acceleration responses in reef limestone under varying explosion depths, explosive equivalents, water depths, and standoff distances. A comprehensive evaluation model was subsequently developed by integrating the KMO-PCA-clustering algorithm. The results demonstrate that: (1) Decrease in explosion depth, increase in standoff distance, and reduction in water depth were all found to weaken the dynamic disturbance of rock masses. Although increasing explosive equivalent enhances response intensity, the efficiency improvement demonstrates a nonlinear imbalance with carbon emissions; (2) Based on the KMO-PCA comprehensive evaluation index system, velocity was identified as the core regulatory factor of dynamic responses, with the S7 test case inducing the most severe dynamic disturbance on reef limestone; (3) Cluster analysis of carbon emissions-comprehensive scores verifies the dual benefits of blast parameter optimization in enhancing efficiency and reducing carbon emissions; (4) The carbon emission calculation formula derived from the Sadovsky formula and carbon emission accounting model provides theoretical support and practical references for blast-resistant design of island-reef protection engineering and optimization of green blasting technologies.