2020 Fiscal Year Final Research Report

Study for repair with seismic performance of Kumamoto Castle stone wall which is a cultural heritage

Research Project

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Project/Area Number	18H01526
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 22020:Structure engineering and earthquake engineering-related
Research Institution	Kokushikan University
Principal Investigator	HASHIMOTO TAKAO 国士舘大学, 理工学部, 教授 (40628814)
Co-Investigator(Kenkyū-buntansha)	酒井久和法政大学, デザイン工学部, 教授 (00360371) 池本敏和金沢大学, 地球社会基盤学系, 講師 (60311677) 宮島昌克金沢大学, 地球社会基盤学系, 教授 (70143881) 若井明彦群馬大学, 大学院理工学府, 教授 (90292622)
Project Period (FY)	2018-04-01 – 2021-03-31
Keywords	熊本地震 / 熊本城 / 石垣 / 補強 / 城壁 / 耐震対策 / 振動実験 / 非破壊検査
Outline of Final Research Achievements	In the 2016 Kumamoto earthquake, more than 80% of the Kumamoto castle stone walls that had been restored so far collapsed again. However, its collapse mechanism and reinforcement measures have not been established. Therefore, we made a three-dimensional model of the ground using the latest non-destructive inspection and geophysical exploration techniques, and clarified the collapse mechanism of the stone wall by advanced analysis. In addition, full-scale experiments were conducted on the large shaking table of the National Research Institute for Earth Science and Disaster Prevention for six types of existing and new stone wall restoration and reinforcement measures. As a result, effective reinforcement measures that can be constructed at Kumamoto Castle have been clarified. This research result was adopted as the "Kumamoto Castle Ishigaki Seismic Diagnosis Guideline" by the Agency for Cultural Affairs for earthquake resistance measures for Kumamoto Castle Ishigaki.
Free Research Field	地震工学、地盤工学、防災工学
Academic Significance and Societal Importance of the Research Achievements	本研究では、熊本城の石垣が2016年熊本地震により崩壊した原因について最先端技術を利用して地盤と石垣を３D化した解析により明らかにした。また、熊本城石垣が崩壊・孕み箇所を復旧する補強対策がなかったため、防災科学技術研究所で熊本城の実物大の断面構造で熊本栗石を用いた大型振動台実験・解析により効果的工法を提案した成果を挙げた点に学術的意義がある。また、本研究の成果が、熊本城の石垣の耐震対策を進めるにあたって推奨される標準的な手順と方法、補強を行うにあたって取り得る補強方法と留意点について示す文化庁「熊本城石垣耐震診断指針（案）」として実際の熊本城修復工事に活用されたことに社会的意義がある。