1990 Fiscal Year Final Research Report Summary
PullーOut Mechanism of Geogrid in Soil and Its Application to the Design Method of Earth Reinforced Soil Wall
| Project/Area Number |
01460179
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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 |
基礎・土質工学
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| Research Institution | Kyushu University |
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Principal Investigator |
OCHIAI Hidetoshi Kyushu Univ., Civil Engin. (Suiko) Professor, 工学部, 教授 (00039679)
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| Co-Investigator(Kenkyū-buntansha) |
OGISAKO Eiji Shimizu Corporation, Civil Engin. Div. Visiting Scholar, Kyushu University, 土木本部, 九州大学研究員
UMEZAKI Takeo Kyushu Univ., Civil Engin. (Suiko) Research Associate, 工学部, 助手 (50193933)
OTANI Jun Kyushu Univ., Civil Engin. (Suiko) Research Associate, 工学部, 助手 (30203821)
HAYASHI Shigenori Kyushu Univ., Civil Engin. (Suiko) Associate Professor, 工学部, 助教授 (80112308)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Polymer grid / Pullーout test / Retaining wall / Sand / Finite element method / Design / Earth pressure / Interaction |
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| Research Abstract |
Earth Reinforcement by using geogrid has been widely applied to soil structures, such as embankments, slopes, retaining wall and foundations, but the design method which evaluates the reinforcing effect properly has not been established.
The objectives of this research are to make clear the mechanism of geogridーearthーreinforcement under pullーout forces, to develop an evaluation method of the reinforcing effect, and to establish the design method of the reinforced soil wall. For the purposes, a series of pullーout tests of geogrid in soil was conducted under different relative density of soil. The mechanism of the pullーout resistance of geogrid in soil was clarified by discussing the interaction properties between soil and geogrid from the test results. The mechanism was modeled and formulated as a shearing property in the joint element to take it into finite element method.
Main conclusions are summarized as follows :
1) Strain distribution on the geogrid in soil is not uniform under pullーout forces, and the corresponding pullーout resistance is the same property, so that the reinforcing effects depends on the relative displacement between soil and geogrid.
2) The reinforcing effect was evaluated by finite element analysis which the pullーout mechanism was introduced in the shearing property of joint element.
3) From the analysis results of the reinforced soil wall, it was shown that the design papameters were the maximum lateral displacement of the wall, the maximum settlement of the foundation, vertical stress in the foundation and maximum tensile force of geogrid.
4) A design method for geogridーreinforcedーsoilーwall, which is based on the charts in terms of the design papameters described above, was proposed.
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