1991 Fiscal Year Final Research Report Summary
A Study of the Occurrence Mechanism, the Prediction and Prevention Works of Landslides by the Groundwater Flow Analysis
| Project/Area Number |
01460234
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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 University |
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Principal Investigator |
YOSHIDA Shoji Niigata Univ. Fac. of Agriculture Professor, 農学部, 教授 (80018530)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHAMA Nobuyuki Niigata Univ. Res. Inst. for Hazards Assoc. Prof., 積雪地域災害研究センター, 助教授 (20018948)
SATO Osamu Niigata Univ. Res. Inst. for Hazards Professor, 積雪地域災害研究センター, 教授 (00022624)
NAKANO Toshio Niigata Univ. Fac. of Agriculture Assoc. Prof., 農学部, 助教授 (40018544)
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| Project Period (FY) |
1990 – 1991
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| Keywords | landslide / groundwater level / water quality / pore water pressure / hydraulic conductivity / finite element method / stability analysis / observation of groundwater |
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| Research Abstract |
(1) The vertical distribution of water quality in the observation borehole with a screened section along all its length is generated as the results that the groundwater having the highest potential infiltrates into the borehole through its wall and diffuses vertically. And therefore the distribution of water quality in the borehole disagrees with one of groundwater being adjacent to the borehole.
(2) We obtained the following findings from the numerical analysis and the sand model experiments : In such inclined groundflow as one in landslide slopes the water level in the observation borehole having a screened section along all its length disagrees with but appears below the original free surface of groundwater.
(3) A simple finite elements method analyzing steady groundwater flow with a free surface is proposed. This method is applied to all the region involving the unsaturated zone without mesh iteration under the condition of which the hydraulic conductivity is constant in the unsaturated zone. The method can be applied with ease to a wide variety of problems involving complex boundaries and arbitrary degrees of heterogenity. Owing to this method it will be very easier to obtain the pore water pressure along the slip surface which is necessary to the stability analysis of landslide slopes.
(4) In the stability analysis the vertical distribution of the ground water pressure should not be assumed static in the landslide slopes which have inclined unconfined groundwater flow and which have -the multi-s, Lratums with different permeabilities.
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