Development of an open-wing type anchor method for reinforcement of large scale residential land on embankment

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04354
• 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: Ritsumeikan University
• Principal Investigator: Fukagawa Ryoichi 立命館大学, 理工学部, 教授 (20127129)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 拡翼アンカー / 鉄筋挿入工 / 盛土斜面 / 補強 / 室内モデル試験 / 原位置試験

Outline of Final Research Achievements

An open-wing type anchor, abbreviated as OW anchor, method was developed in this study. At first, reliable open-wing mechanism in a borehole was proposed and it was demonstrated by FEM that the structure of the open-wing mechanism had enough strength to withstand pulling out. Next, a series of pulling out experiments using model OW anchor was carried out for laboratory model sandy ground and actual some in-situ grounds. As the results, it was made clear that the OW anchor generated enough pulling out resistance. On the other hand, a theoretical estimation method of pulling out resistance by OW anchor was proposed, and showed a good accordance with experimental data. Finally some slope failure tests were conducted in laboratory conditions. The model slope experienced heavy rain and was reinforced by some one-tenth size of actual OW anchors. The results showed that the OW anchor generated effective pulling out resistance to reinforce the model slope.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

従来型のアンカーでは、中心ロッドと周辺地山をセメント等の固化剤で接着させることが引抜抵抗力の源である。この接着効果は経年的に低下していくことが知られており、社会問題となっている。本研究で提案した拡翼アンカーは、先端の拡翼部で地盤を物理的に把持するため、その効果は減衰しにくい。アンカー工法は斜面安定の中心的な工法の1つであり、したがって拡翼アンカーの開発の社会的意義は大きい。本研究の学術的意義としては、信頼性の高い拡翼メカニズムを提案しその有効性を実証したこと、拡翼アンカーの引き抜き抵抗の推定式を提案したこと、モデル地盤および原位置地盤で拡翼アンカーの有効性を実証したこと等を挙げることができる。