Dynamics of impact force wave in soil due to rock fall: paradigm shift of rock fall protection by using soils

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02241
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• 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)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 落石 / 落石対策 / 緩衝効果 / 粒状体 / マルチスケール / 二重性 / マイクロメカニクス / 個別要素法

Outline of Final Research Achievements

This study has attempted to visualize the previously overlooked phenomena of local deformation behavior and transferred stress in the soil through impact experiments and discrete element method analysis that incorporate measurements using image analysis. We also observed soil not only at the continuum level, as in the past, but also at multiple scales, such as the particle level and the particle skeleton level, and investigated the buffering mechanism from the interaction between them. Furthermore, the buffering behavior of the impact force was viewed in terms of the dual nature of the particle body (particle nature) and the nature of propagation as waves (wave nature), in which the particles' characteristics are clearly expressed. The elucidation of the mechanism of the buffering effect of soil focusing on the multi-scale and dual nature is an interdisciplinary achievement that straddles physics, impact engineering, geotechnics, and structural mechanics and is unique in the world.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

土を利活用した緩衝材の落石のエネルギー吸収能力や衝撃力伝播特性の評価は斜面防災や落石対策工の長寿命化において重要で科学的にも魅力的な課題である。そこで、土の粒子レベル、応力が集中する粒子骨格を意味する応力鎖のレベルや連続体レベルのマルチなスケールの視点で、従来は見落とされていた衝撃力の伝達メカニズムを解明した。模型実験方法や数値解析方法の開発を行い、応力鎖の発生・消滅、亀裂や塑性波の伝播、密度変化などを可視化した。土―構造物系の衝撃応答を深く理解し、土を積極的に利活用することで落石対策工の効率化・長寿命化方法を提案し、落石対策のパラダイムシフトに大きく貢献した。