| Project/Area Number |
60460210
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
農業土木
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| Research Institution | Niigata Univcrsity. |
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Principal Investigator |
YOSHIDA Shoji The Research Institute for Hazards in Snowy Areas Niigata University Professor, 積雪地域災害研究センター, 教授 (80018530)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Toshiro Department of Agriculture Assistant, 農学部, 助手 (40018544)
SATO Osamu The Research Institute for Hazards in Snowy Areas Niigata University Associate P, 積雪地域災害研究センター, 助教授 (00022624)
NAGASAKI Akira Department of Agriculture Professor, 農学部, 教授 (80018514)
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1987: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1986: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1985: ¥400,000 (Direct Cost: ¥400,000)
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| Keywords | Landslide / Pore water pressure / Groundwater / Water chemistry / Drainage / 水質 / 稲作慣行 / 乾田化 / 地下水 / 間隙水圧 / 安定解析 / 安全率 |
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| Research Abstract |
Investigation of groundwater at Matunoyamakoshi landslide in Niigata Prefecture were made in 1986 87 after the occurunce of the reactive landslide in the spring 1985 by the developed automatic observation system. This system can automatically recorded several months observation data into an IC card even under beep snow in winter.The results obtained are as follos.
Unconfined groundwater level which exists in old landslide debris of thickness up to about 6 m below the ground surface has been nearly constant near the ground surface in all seasons and was scarcely influenced by both water supply due to tainfall and drainage due to boring works. Conversly, groundwater pressure in the weathering mudstone underlying below the unconfined groundwater decreased with the drainage works. Pressure of groundwater outside the area of the slip was easily influenced to the rise by rainfall, in contrast with groundwater whithin the area of the slip. From above and other results, it may be assumed that the slip surface clay which had been produced during the preceding slip constitutes a nearly impermeable layer.
Main components of groundwater around the slip surface in the landslide were analyzed to trace the behavior of groundwater which acted as a trigger of sliding. The sodium chloride type water originated from the fossil sea water was observbed in the weathered tuff underlying the slip suoface.
It is concluded that drainage of this confined groundwater is necessary to cotroll reactivation of landslide from the investigation of groundwater pressure and tracing the water.
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