Study on biodeterioration and long-term durability of logs in reclaimed land

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06170
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40020:Wood science-related
• Research Institution: Kochi University
• Principal Investigator: Hara Tadashi 高知大学, 教育研究部自然科学系理工学部門, 教授 (80407874)
• Co-Investigator(Kenkyū-buntansha): 堀澤 栄 高知工科大学, 環境理工学群, 教授 (20368856)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 埋立地盤 / 丸太 / 生物劣化 / 耐久性

Outline of Final Research Achievements

In this study, the permanence of the ground improvement effect of the Log Piling Method for Liquefaction Mitigation and Carbon Stock developed by the applicants was proved based on quantitative data. Logs buried in reclaimed ground for a long period of time were collected locally, and the presence or absence and degree of biological deterioration, which is a weak point when using wood as a ground improvement material, was investigated from the viewpoint of geotechnical and wood engineering.
As a result, several experiments have shown that the long-term durability of logs is maintained in the reclaimed ground and the ground improvement effect is exhibited semi-permanently. Furthermore, the usefulness, certainty, and reliability of the environment-friendly ground improvement method using logs were evaluated from the field observations of the reclaimed ground improved by the LP-LiC method.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

我が国の豊富な森林資源を積極的に利用し，発生確率の高い南海トラフ地震などによる液状化被害を軽減させるための具体的な方法として，筆者らは環境負荷型の従来工事に比べ地球温暖化対策にも配慮した丸太を用いた対策工法を提案している。鋼やコンクリートなどの人工材料が普及する我が国において，不明確な点の多い埋設後の丸太の健全性や機能性，効果の永続性を生物劣化の観点から分析し，木材が断面欠損することなく改良効果が半永久的に発揮される事実を定量的結果で示した。木材を利用するうえで障害となっている要因が解消され，純国産資源で長い歴史を持つ木材を液状化対策に積極的に活用するための一助になることを期待している。