中文摘要：

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的影响不大,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地减弱滚石冲击对棚洞钢筋混凝土顶板造成的变形影响,但同时也会增加结构自重;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。

英文摘要：

In the top of the rock-shed,a certain thickness of sand cushion could play a significant energy dissipation function. The effect of different thickness of sand cushion is greatly diverse. Hence,how to determine the thickness of sand cushion became one of the key issues in the shed design. Based on the actual shed tunnel structures as prototypes,the dynamic finite element numerical simulation was used to analyze the dynamic response of sand cushions with multi thickness under different impact energies and the mechanism of energy absorption. The results showed that under low impact energy,the changes of sand cushion thickness had little influence on the rock fall impact force,whereas there were extremely differences in the energy absorption of different thickness sand cushions under high impact energy. Increasing the thickness of sand cushions could effectively weaken the slabs＇ deformation caused by rock fall impact,however enlarged the weight of structures. With the consideration of both economic rationality and structural reliability,the optimal cushion thickness was obtained by calculation.