Failure mechanism for gravel mixed soil due to bucket excavation and estimation on its shear strength parameters

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04592
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Tohoku University
• Principal Investigator: Satomi Tomoaki 東北大学, 環境科学研究科, 助教 (80588020)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 地盤情報施工 / バケット掘削 / 力覚 / 礫混じり土 / 掘削実験 / X線CT / 地盤強度 / クーロンの破壊基準

Outline of Final Research Achievements

Unmanned construction is required for sediment disaster reconstruction work, and thus understanding a ground strength is significant to improve the work efficiency. To develop a ground strength estimation method using an excavator bucket, the present study investigated bucket excavation of soil mixed with gravel, which has been overlooked in terramechanics research dealing with mechanical interaction between soil and construction machinery. Specifically, this study clarified the effects of gravel on the relationship between soil failure patterns and change in excavating resistive force by bucket and ground strength through two-and three-dimensional and X-ray CT excavation tests and low confining pressure typed box shear tests. In addition, this study proposed a method for estimating shear strength parameters using the resistive force acting on the bucket.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

災害復旧作業での安全性確保の観点から無人化施工のニーズが高まっている。しかし，現状は車載カメラの画像に頼っているため，有人施工と比べて効率が悪い。よって，「機械で掘削しながら地盤の強度を評価する」という新しい観点が不可欠である。しかし，バケット掘削における実地盤のような礫混じり土の破壊メカニズムは明らかにされていない。そこで本研究では，掘削実験と低拘束圧中型一面せん断試験を通じてバケットに作用する抵抗力の変化と地盤強度との関係に及ぼす礫の影響を明示した。そして，掘削抵抗力を用いた地盤強度推定法を提案できたことは，無人化施工の効率向上に貢献する技術の開発につながると期待される。