Study on mechanism of slope failure caused by pipe flow

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K16379
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: National Institute of Occupational Safety and Health,Japan
• Principal Investigator: Hiraoka Nobutaka 独立行政法人労働者健康安全機構労働安全衛生総合研究所, 建設安全研究グループ, 研究員 (00756546)
• Research Collaborator: Tanaka Katsuhiko 立命館大学, 総合科学技術研究機構, 上席研究員 (00367997) ; Fujimoto Masamitsu 立命館大学, 理工学部, 准教授 (60511508)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 斜面崩壊 / パイプ流 / 地下水 / モニタリング / 土砂災害

Outline of Final Research Achievements

About pipe flow in the ground causing sediment disaster, it was verified whether the pipe flow could be detected by measuring the water level and the effect. In long-term measurements on natural slopes, it was observed that the deep layer responds faster to rainfall than the shallow layer. Therefore. It was suggested that there was a pipe flow and a water path near such a point. In the laboratory experiment, the pipe flow has drainage effect on slopes with saturated zones, and when the water level is measured at multiple points, the water level tends to be lower the closer to the pipe flow. When water exceeding the allowable flow rate of the pipe flow was supplied due to heavy rainfall, or when the pipe flow was blocked, water permeated from the pipe flow to the slope and collapsed.

Free Research Field

地盤工学

Academic Significance and Societal Importance of the Research Achievements

降雨による土砂崩壊の一因とされているパイプ流の影響について，自然斜面における長期水分・水位計測によって位置や傾向が計測できることが確認できた。また，室内実験によって，パイプ流をもつ斜面が降雨によって崩壊に至るメカニズムが確認できた。これらの成果によって，より精度の高い斜面崩壊危険予測が期待でき，防災・減災に貢献できる。