Dynamic Characteristics of EICP-Stabilized Fiber-Reinforced Sand Under SHPB Loading

Calcareous sand is widely used in marine and island reef engineering; however, its low strength and severe particle breakage are further exacerbated under dynamic loading, making the dynamic performance of reinforced calcareous sand critical to engineering safety. Nevertheless, research on the dynamic characteristics of EICP/MICP-reinforced calcareous sand remains very limited. The dynamic performance was evaluated using Split Hopkinson Pressure Bar (SHPB) tests, and the results were compared with UCS data to examine the effects of particle gradation and fiber content on both dynamic and static behaviors. The results show that dynamic strength increases with calcium carbonate content (CCC) and impact pressure. Under the same CCC, the dynamic strength is consistently higher than the static strength, with a maximum difference of up to 2.5 MPa. Fiber incorporation significantly enhances structural integrity, and SEM analysis reveals that this improvement stems from effective bonding between fibers and cementitious materials. Based on the static and dynamic test results, the optimal mix ratio for EICP-reinforced calcareous sand is determined as 50% coarse sand content and 0.4% fiber content by mass, which provides theoretical support and design parameters for sustainable green reinforcement of calcareous sand foundations in marine and island reef engineering.