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New light-weight concrete foam to absorb debris-flow-entrained boulder impact: Large-scale pendulum modelling
Engineering Geology ( IF 6.9 ) Pub Date : 2020-09-01 , DOI: 10.1016/j.enggeo.2020.105724
Y. Su , C.E. Choi , C.W.W. Ng , H.W.K. Lam , L.A. Wong , C. Lee

Abstract Rock-filled gabions are widely used to attenuate concentrated impact loads exerted by boulders entrained in debris flows. However, rock fragments used to construct gabion may not always be available and the performance of rock-filled gabion can be highly variable, depending on size and angularity of the rock fragments used. In this study, light-weight concrete foam is proposed as an alternative cushioning material to overcome some of the limitations of rock-filled gabion. Physical large-scale pendulum impact tests were conducted to study the performance of concrete foam, which was used to shield a reinforced concrete barrier from boulder impact. Six successive boulder impacts were carried out at energies of up to 70 kJ. Two different concrete foam thicknesses, 0.4 m and 0.6 m, were investigated. Increasing the cushioning thickness from 0.4 m to 0.6 m can reduce the maximum transmitted load by 48% and 71% for the first and sixth impacts at an impact energy of 70 kJ, respectively. The larger cushioning thickness enhances load spreading on the wall and reduces stress concentration. Furthermore, the maximum penetration depth on the 0.4-m thick concrete foam is 0.29 m for the sixth impact at an impact energy of 70 kJ, which is equivalent to 72% of the initial cushioning layer thickness. Based on the existing design guidelines (ASTRA 2010) and the Gibson and Ashby model, the required minimum thickness for up to six successive impacts at an impact energy of 70 kJ is 0.58 m.

中文翻译:

用于吸收泥石流夹带的巨石冲击的新型轻质混凝土泡沫:大型钟摆建模

摘要 填石石笼广泛用于减轻泥石流夹带的巨石所施加的集中冲击载荷。然而,用于建造石笼的岩石碎片可能并不总是可用的,并且填石石笼的性能可能变化很大,这取决于所用岩石碎片的大小和角度。在这项研究中,轻质混凝土泡沫被提议作为一种替代缓冲材料,以克服岩石填充石笼的一些局限性。进行了大规模的物理摆锤冲击试验,以研究混凝土泡沫的性能,该泡沫用于保护钢筋混凝土屏障免受巨石冲击。在高达 70 kJ 的能量下进行了六次连续的巨石撞击。研究了两种不同的混凝土泡沫厚度,0.4 m 和 0.6 m。将缓冲厚度从 0 增加。4 m 到 0.6 m 可以分别在 70 kJ 的冲击能量下将第一次和第六次冲击的最大传递载荷降低 48% 和 71%。较大的缓冲厚度可增强负载在壁上的分散并减少应力集中。此外,在 70 kJ 的冲击能量下,0.4 米厚的混凝土泡沫的最大穿透深度为 0.29 米,相当于初始缓冲层厚度的 72%。根据现有的设计指南 (ASTRA 2010) 和 Gibson 和 Ashby 模型,以 70 kJ 的冲击能量进行最多六次连续冲击所需的最小厚度为 0.58 m。较大的缓冲厚度可增强墙壁上的载荷分布并减少应力集中。此外,在 70 kJ 的冲击能量下,0.4 米厚的混凝土泡沫的最大穿透深度为 0.29 米,相当于初始缓冲层厚度的 72%。根据现有的设计指南 (ASTRA 2010) 和 Gibson 和 Ashby 模型,以 70 kJ 的冲击能量进行最多六次连续冲击所需的最小厚度为 0.58 m。较大的缓冲厚度可增强墙壁上的载荷分布并减少应力集中。此外,在 70 kJ 的冲击能量下,0.4 米厚的混凝土泡沫的最大穿透深度为 0.29 米,相当于初始缓冲层厚度的 72%。根据现有的设计指南 (ASTRA 2010) 和 Gibson 和 Ashby 模型,以 70 kJ 的冲击能量进行最多六次连续冲击所需的最小厚度为 0.58 m。
更新日期:2020-09-01
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