Development of stability evaluation method for masonry retaining walls against multi-hazards of earthquake and rainfall

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K14827
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22030:Geotechnical engineering-related
• Research Institution: Hiroshima University
• Principal Investigator: Hashimoto Ryota 広島大学, 先進理工系科学研究科(工), 准教授 (60805349)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 石積壁 / 石垣 / 数値解析 / MPM-DDA / 浸透－変形連成解析 / FDM

Outline of Final Research Achievements

In recent years, many masonry walls have experienced earthquakes, resulting in deformation and then collapse due to strong rainfall. In this study, we developed a technique to analyze the behavior of masonry retaining walls from deformation caused by an earthquake to collapse caused by the next external force, such as another earthquake or rainfall, in a series of events.
First, a coupled method of MPM and discontinuous deformation analysis (DDA) was developed to analyze the dynamic behavior of masonry walls, including the collapse of backfill soil. Then, in order to take into account water infiltration into the ground, MPM is coupled with finite difference analysis based on the Darcy-Brinkman equation to take into account soil-water coupling phenomena.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

本研究以前に実施された石積壁の数値解析には個別要素法（DEM）や有限要素法（FEM）が用いられている。しかし、前者は地盤の構成関係や間隙圧挙動を反映できず、後者は地盤の構成則を利用できるが、不連続な壁面部材の大変形の表現は難しく、別個に検討されており、また、土中への浸透現象は考慮されてこなかった。
本研究では研究代表者がこれまで整備してきた陰解法に基づく地盤－石積構造物間の相互作用解析コードを地盤の大変形と水の浸透現象へと拡張させた。これにより、従来手法では困難だった石積壁を含む柔構造擁壁の地震・降雨のマルチハザードに対する応答のシームレスな予測・評価が可能となる。