Quantitative Evaluation of Mechanical Stability for Improving Disaster Resilience of Castle-Built Stone Structures

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K05030
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Nagasaki University
• Principal Investigator: Sugimoto Satoshi 長崎大学, 工学研究科, 准教授 (60404240)
• Co-Investigator(Kenkyū-buntansha): 石塚 洋一 長崎大学, 工学研究科, 教授 (50284708)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 築石構造物 / 変状 / 力学的安定性 / 個別要素法 / 遠心力載荷模型実験

Outline of Final Research Achievements

Following four points were addressed. (1) Installation and operation of a multi-point deformation monitoring system, (2) evaluation of the surface shape of deformed stonewalls and vibration characteristics of unstable stonewalls, (3) implementation of dynamic model experiments of built stone structures using a medium-sized centrifuge, and (4) evaluation of the mechanical stability of castle stonewalls using individual element method analysis. Based on the results of (3), we clarified the validity of the evaluation method in (4), and evaluated the mechanical stability of the current altered stone wall of Kumamoto Castle based on the results of (1), (2), and (4), and classified the collapse patterns based on the relationship between the roughness of the stone surface and the chestnut stone layer width that constitutes the stone wall, which was based on the results of (4). This quantitatively showed the degree of risk of collapse due to seismic motion for each basic stone wall structure.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

本研究は，従来の経験則による文化財保護的観点ではなく，地盤工学的手法を用いた工学的観点より，城郭石垣の崩壊予測や崩壊に対する安全性評価を定量化することで，より安全な工事の遂行や，観光客等の安全確保のために必要な判断基準を，城郭を管理する行政や管理者が設定する上で、工学的根拠に基づく情報を提供することが可能となる。これにより、城郭石垣の維持管理や被災対象の復旧の要否といった実務的課題を解決する一助となることに意義を有する。