| Project/Area Number |
14560196
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | Niigata University |
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Principal Investigator |
MORII Toshihiro NIIGATA UNIVERSITY, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (30231640)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Riprap work / Overtopping flow / Rockfill / Head loss equation of flow / Hydraulic mean radius of voids / Laboratory water flume tests / オーバートッピング(越流) / 流れの非線形水頭損失特性 / 土砂の透水性 / 捨石工(リップラップ工) / 水理学的安定性 / 浸食メカニズム / 流れの水頭損失 |
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| Research Abstract |
The purpose of the Research Project Is to investigate hydraulic and mechanical properties of rockfill and to propose a design procedure of riprap work that effectively resist against overtopping flow on soil embankment. Rock has been advantageously employed in hydraulic structures such as rockfill dams, flow-through embankments, rubble weirs and riprap works. To predict a flow transmissibility of the rockfill structure, an accurate evaluation of head loss property of flow through rockfill is required. In the Research Project, a head loss equation of flow through rockfill that is applicable to a wide range of rock particle size is proposed. A quadratic equation is selected to describe the head loss property of flow through rock fill. Two nonlinear coefficients included in the equation are effectively determined as a function of a hydraulic mean radius of rockfill voids based on laboratory tests using river gravel 5 to 75 mm in diameter. It is shown that the head loss equation of flow determined can be well applied to predict the flow transmissibility of rockfill structures without any consideration of scale effect of flow. A numerical experiment is conducted to estimate an amount of laminar flow composing the flow through rockfill. The laminar flow is found to be negligible even in the flow through a small size structure constructed using small rock particles. A parameter estimation procedure that employs a simple genetic algorithm combined with FEM calculation is also developed to determine the nonlinear coefficients in the head loss equation from a stage-discharge rate data observed in the laboratory or in the field/ Investigations of the mechanical property of rockfill as well as of soil erosion in an underlying foundation that have been left behind this two-year project will be tackled successively by the Head Investigator.
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