Shock absorbing mechanism of soil and countermeasures for expanding the lifespan of rockfall protection works by using soil

2016 Fiscal Year Final Research Report

• Project/Area Number: 26289152
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Geotechnical engineering
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Maeda Kenichi 名古屋工業大学, 工学(系)研究科(研究院), 教授 (50271648)
• Research Collaborator: USHIWATARI Yuji ; YAMAGUCHI Satoru ; SAKAKIBARA Junichi ; KOBAYASHI Tsuyoshi ; KOIKE Yutaka ; Muir WOOD David
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 応力波 / 密度 / 緩衝 / 衝撃力 / 伝播 / マイクロメカニクス / マルチスケール / 速度以前

Outline of Final Research Achievements

Cushioning materials, such as sand cushion and granular mats placed on rock sheds, can effectively disperse and reduce rock fall energy before rocks collide with protection works. Although the construction costs for sedimentary layers are low, these layers are attracting attention as construction devices that can substantially improve the margin of safety ratio. To elucidate the mechanism that governs the impact force waveform of falling mass, this study examines the loading rate dependency of sand cushion by DEM simulation. In the simulation, particular attention is paid to the velocity of stress waves that propagate in sand cushion.
For responding to a wider range of falling rocks impact by absorbing system using soils, we carried out falling-weight impact test against alternating layers absorbing systems. Upper and under layers of alternating layers is composed of sand and middle layer is composed of gravel.

Free Research Field

地盤工学