Study on steel fiber synergistically reinforced cellular concrete explosion-proof effect in an underwater near-field environment

Based on the static and dynamic test results of steel fiber synergistically reinforced cellular concrete (SFSRCC) under a complex stress state, the yield surface equation and strain rate effect are modified to construct a modified Holmquist-Johnson-Cook (HJC) model suitable for the dynamic compression behavior characteristics of SFSRCC, and the modified HJC model is verified. At the same time, a finite width SFSRCC protective layer-roller compacted concrete (RCC) slab-water-explosive multimedia coupling model is established to explore the influence of setting different thicknesses of the SFSRCC protective layer (0, 0.1, 0.2, and 0.3 m) on the explosion-proof performance and effect of the RCC slab structure. The results show that the heavy stress-strain curves and dynamic failure modes of the SFSRCC under different strain rates are in good agreement with the experimental results. The maximum errors of peak stress and peak strain between the simulation results and the experimental results are 1.04% and 6.6%, respectively, which confirms the validity of the HJC correction model and the accuracy of the simulation results. After setting different thicknesses of the protective layer, the RCC slab blast crater depth is reduced by 56.7%, 80%, and 93.3% compared with that at 0.18 m without a protective layer program, and almost no damage to the back explosion surface occurs. The failure volume ratio of the protected RCC slab structure gradually decreases from 38.53% to 3.24% with increasing protective layer thickness, and the protected RCC slab shows only slight damage after setting the protective layer. When the thickness of the protective layer is 0.3 m, the damage of the protected RCC slab structure is distributed in the surface area, which has little effect on the structural safety. These results show that the additional SFSRCC protective layer under the condition of underwater near-field explosion can significantly reduce the damage degree of the slab structure and improve the explosion-proof performance of the protected RCC slab structure. This research offers a theoretical reference for the explosion-proof material selection and design of hydraulic structures and explosion-proof application of SFSRCC under the action of underwater explosion impact loads.