Triaxial experimental study on mechanical behavior, acoustic emission characteristics, and energy evolution of coral sand grouting consolidated body under different confining pressures

This study conducted triaxial compression tests on coral sand grouting consolidated body, incorporating Acoustic Emission (AE) testing to analyze the mechanical properties, AE characteristics, and energy evolution under different strain rates. The results indicated that peak stress, axial peak strain, radial peak strain, and elastic modulus positively correlated with increasing strain rates and confining pressures. The Bresler-Pister (B-P) failure criterion demonstrated superior accuracy in predicting strength values, with prediction errors constrained within 1.5 MPa. Based on AE parameters, the distribution of ringing counts, b-values, and RA-AF (rise time/maximum amplitude and average frequency) values in the grouting consolidated body exhibited significant and distinguishable variations at different failure stages. Energy analysis revealed that dissipated strain energy increased continuously with axial strain, whereas elastic strain energy initially increased before decreasing, peaking at the maximum stress level. The ratio of dissipated strain energy to total peak energy increased with strain rate and confining pressure, with dissipated strain energy comprising approximately 65 % of the total input energy at a confining pressure of 10 MPa, suggesting that a significant portion of the total input energy was converted into dissipated energy. The findings of this study offer valuable theoretical insights and practical engineering implications for grouting reinforcement of coral sand foundations in island reef regions.