Effects of particle-size distribution on buffering mechanism of waste concrete aggregate cushion layer under impact load

被引：0
作者：
Su, Yuchen [1 ]
Li, Pengfei [1 ]
Zhong, Heng [1 ]
Wu, Lin [1 ]
Wang, Yuan [2 ]
Lu, Yarn [1 ]
机构：
[1] College of Mechanics and Materials, Hohai University, Nanjing
[2] College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing
来源：
Zhendong yu Chongji/Journal of Vibration and Shock | 2024年 / 43卷 / 09期
关键词：
buffering performance; dynamic load; particle rearrangement; particle-size distribution;
D O I：
10.13465/j.cnki.jvs.2024.09.003
中图分类号：
学科分类号：
摘要：
Laying a loose material cushion layer above protective structures of shed tunnels, etc. can significantly reduce impact force of falling rocks and transmission force of shed roof to improve anti-impact performance of protective structures. Here, to study effects of particle-size distribution on buffering performance of new type waste concrete aggregate cushion layer, indoor drop hammer impact tests and 3-D discrete element numerical simulation were conducted, respectively. The results showed that for cushion layer with same particle size, when the homogenized particle size d50/R increases from 0. 15 to 0. 75, due to potential instability points in force chain decreasing, the stability of force chain increases, and the particle rearrangement mechanism is limited, average displacement and rotating angle deceases by 41.3% and 33.7%, respectively to cause peak impact force of drop hammer and peak transmission force of shed roof increasing by 36.3% and 282.2%, respectively; for cushion layer with different particle sizes, when the non-uniformity coefficient Cu increases from 1.1 to 8. 0, pores around coarse particles are filled with fine particles, the coordination number increases, the stability of force chain increases, the particle rearrangement mechanism is limited, average displacement and rotating angle decreases by 22. 4% and 45. 3%, respectively and peak values of drop hammer impact force and transmission force of shed roof increase by 26. 0% and 174. 6%, respectively; based on test and numerical simulation results, the cushion layer protection reduction coefficient a is proposed, which is related to the uniform particle size d50/R and the non-uniformity coefficient Cu; a semi-empirical formula for drop hammer impact force considering cushion layer protective action is established to provide technical support and theoretical guidance for design and construction of shed tunnel engineering in mountain areas. © 2024 Chinese Vibration Engineering Society. All rights reserved.
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页码：18 / 26
页数：8
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