Practical study on rainfall water infiltration and slope failure mechanism in natural stratified slopes based on distributed sensor observations

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01584
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Gunma University
• Principal Investigator: Wakai Akihiko 群馬大学, 大学院理工学府, 教授 (90292622)
• Co-Investigator(Kenkyū-buntansha): 佐藤 剛 東京都市大学, 環境学部, 教授 (00468406) ; 木村 誇 愛媛大学, 農学研究科, 助教 (90758559) ; 蜂屋 孝太郎 帝京平成大学, 人文社会学部, 教授 (40540381) ; 高橋 啓 福岡工業大学, 情報工学部, 准教授 (70595280)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 斜面 / 降雨 / 崩壊 / 地下水位 / 観測

Outline of Final Research Achievements

Elemental technologies to improve slope stability evaluation and monitoring methods were examined in this study. Our focus was placed on two points: understanding the slope condition based on aerial surveys, and improving the efficiency of observation and transmission technology. Observation sites for actual slopes (Gogoshima Island in Ehime Prefecture and the Aso Mountains in Kumamoto Prefecture) have been selected to advance our research. As an aerial survey, topographical analysis and supplementary UAV aerial surveys were performed. To improve the efficiency of observation and transmission technology, the elemental devices for real-time transmission of observation data acquired from sensors were improved. Finally, numerical analyses using a groundwater and surface water simulation model (TAG_FLOW) were conducted to simulate the time histories of the groundwater level, safety factor, and surface water depth during rainfall, which were verified the validity for the risk assessment.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

ばらまき型センサーによらなければ実現しなかった，従来にない安価な全斜面的監視システムの構築に向けた斜面観測と再現解析，さらには観測データに基づく解析モデル自身の高精度化，といった総合的な斜面研究を実施した。こうした多点観測システムは，発生箇所を事前予測しにくい自然斜面の広域予測に応用でき，将来のセンサー単価のさらなる低下がこの潮流を強く後押しすることが期待される。観測に基づいて信頼性が向上した力学モデルは，斜面監視の実務において早期に応用可能である。土質力学に適った斜面安定指標を新たに導入することで，例えば，現行の土壌雨量指数のような定性的な指標を精密な力学的観点から補強することに役立つ。