滚石冲击闭孔泡沫铝夹芯板耗能缓冲机理研究

在棚洞顶部铺设一定厚度砂土垫层可起到有效的耗能缓冲作用，不同厚度的砂土垫层耗能缓冲效果差异较大，如何量化砂土垫层厚度成为棚洞结构设计的关键问题之一。以实际棚洞结构为原型，采用动力有限元对滚石冲击砂土垫层进行数值仿真计算，分析不同冲击能量下多组砂土垫层厚度组合的动力响应及耗能缓冲机理。结果表明：低冲击能量下，改变砂土垫层厚度对滚石冲击力影响不大，而高冲击能量下，不同厚度砂土垫层的吸能减震效果有显著差异；增大砂土垫层厚度可有效的减弱滚石冲击对棚洞钢筋混凝土顶板造成的变形影响，但同时会增加结构自重，通过计算，可以得到最优化的垫层厚度，兼顾经济合理性和结构可靠性。研究成果将为滚石多发区棚洞结构砂土垫层的设计提供理论依据。

Study on the Energy Dissipation of Sandy Soil Cushions on the Rock shed Under Rockfall Impact Load

A cushion layer can efficiently protect the structures in mountainous areas from impact damages of rockfall hazard. In this paper, the aluminium foam, as a kind of energy dissipation cushion material, was introduced into rockfall disaster mitigation areas. This type of cushion was composed of aluminium foam with embedded steel plate that was made to be a sandwich board structure. Dynamic response of rockfall impacting the aluminum foam sandwich panels was analyzed by static experiment and dynamic finite element method, revealing the energy dissipation buffer mechanism of aluminium foam sandwich board. The results showed the existence of a wide energy buffer platform in the stress yield stage, which could absorb lots of energy so as to achieve the purposes of energy dissipating. The sandwich board structure could effectively reduce the deflection deformation of the structures. When the embedded steel plate thickness increases, the cushion impact pit depth decreases and the deformation of protected structure center also were decreased remarkably. However, too thick steel plate will increase the overall rigidity of the sandwich panel, and reduce the energy dissipation of the panel. Therefore, the double indexes of deformation and impact force under rockfall impact structure should be comprehensive considered when the structure of aluminum foam sandwich board was designed.