Abstract In the case of the rockfall hazards, multiple rockfall impacts usually occur. To improve the ductility and the multi-impact resistance ability of the rock-shed, geofoam is proposed to replace part of sand, forming a composite cushion. Two types of geofoam are selected in the paper, namely, expandable polyethylene (EPE) and expanded polystyrene (EPS). A systematic experimental study was conducted to compare the properties of EPE and EPS. The compression tests showed that EPE geofoam had better resilience than EPS geofoam. Under the laboratory multi-impact tests, the buffer performance of the sand-EPE composite cushion performed well under the multi-impacts. However, for the sand-EPS composite cushion, the buffer performance became poor with increased impact number. For the thicker geofoam, the buffer performance of the composite cushion changed slightly from the second impact to the fifth impact, especially for the EPE geofoam. Finally, large-scale rockfall experiments were carried out to further study the buffer performance of different cushions. Compared with EPS geofoam, EPE geofoam was more suitable for improving the capability of the composite cushion to resist multi-impacts, as well as to protect the rock-shed under multiple rockfall impacts.

中文翻译：

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砂土复合垫层抗多重冲击试验研究

摘要 在落石灾害中，通常会发生多次落石冲击。为了提高岩石棚的延展性和抗多重冲击能力，提出用土工泡沫代替部分沙子，形成复合垫层。论文选用了两种土工泡沫，即可发性聚乙烯（EPE）和可发性聚苯乙烯（EPS）。进行了系统的实验研究，以比较 EPE 和 EPS 的性能。压缩试验表明EPE土工泡沫比EPS土工泡沫具有更好的回弹性。在实验室多次冲击试验下，砂-EPE复合垫层在多次冲击下的缓冲性能表现良好。然而，对于沙-EPS复合垫，缓冲性能随着冲击次数的增加而变差。对于较厚的土工泡沫，复合垫的缓冲性能从第二次冲击到第五次冲击略有变化，尤其是EPE土工泡沫。最后，进行了大规模的落石实验，进一步研究了不同垫层的缓冲性能。与EPS土工泡沫相比，EPE土工泡沫更适合提高复合垫层的抗多重冲击能力，以及在多次落石冲击下保护石棚。