Soil erosion and run-off mechanism linked with wind and heavy rainfall and its evaluation

2014 Fiscal Year Final Research Report

• Project/Area Number: 24656287
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geotechnical engineering
• Research Institution: Kyushu University
• Principal Investigator: YASUFUKU NORIYUKI 九州大学, 工学(系)研究科(研究院), 教授 (20166523)
• Co-Investigator(Kenkyū-buntansha): OMINE Kiyoshi (60248474)
• Research Collaborator: ARASE Kota ; FURUKAWA Zentaro ; IWAMI Kohei
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 風食・水食 / 土砂流出・侵食 / 不飽和浸透 / 砂漠化 / 土地劣化 / 適応策 / 土砂流出モデル / 限界最大粒径

Outline of Final Research Achievements

In this study, the erosion characteristics of sandy and clayey soils due to linkage of wind and water forces are investigated by experimental and analytical approaches in order to give a basic idea not only for combating progress of desertification in arid area, but also for solving the sediment runoff problem in Okinawa area due to heavy rainfall.
At first, the relationship between wind speed and soil loss were evaluated paying attention to the initial density and water contents of sandy soils. The surface shear resistance of sandy soil increases with just increasing the water contents from almost zero initial water contents. Secondly, the limit wind speed increases about 40% comparing with the case in dry condition when the water contents of surface soil slightly increase. Furthermore, a simple model for estimating the soil loss as mainly due to rainfall is presented. The proposed model gives a good agreement with the small size model test results under various rainfall strengths.

Free Research Field

地盤工学