STUDY ON THE IMPACT CUSHIONING PERFORMANCE AND STRUCTURAL OPTIMIZATION OF A MODULAR COMPOSITE BUFFERING STRUCTURE

The traditional concrete rockfall shed, relying on a sand cushion for impact energy absorption, suffers from limited buffering performance, long recovery cycles, and inadequate resilience in emergency disaster prevention. To address these issues, this paper proposes a modular composite buffering structure comprising a flexible steel buffer and a sand cushion. A 500kJ impact test was conducted on the structure to investigate its mechanical behavior and rockfall cushioning performance. The test revealed the energy dissipation mechanism between the flexible steel buffer and the sand. Using the LS-DYNA platform, a FEM-DEM coupled dynamic numerical model was established to compare the cushioning performance of the buffering structure with other typical cushions. Additionally, the supports under the concrete slab and the structural layout of the flexible buffer were optimized to achieve better buffering and structural perfoemance. The research demonstrates that the composite buffering structure exhibits excellent cushioning performance, remaining intact under 500 kJ impact. Compared to sand material and EPS-sand cushion, the composite buffering structure reduces impact force by 62% and 20%, respectively. After replacing the supports under the slab by buckling corrugated tubes, the composite system is able to bear 1000kJ impact and the slab’s bearing capacity is improved. With its superior cushioning performance, the composite buffering structure shows great potential for engineering applications.