2002 Fiscal Year Final Research Report Summary
Reinforcement for Upgrading Earth Structures Using Geocomposites under Cyclic Loading
| Project/Area Number |
12555140
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Geotechnical engineering
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| Research Institution | IBARAKI UNVERSITY |
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Principal Investigator |
YASUHARA Kazuya lbaraki Univ., College of Eng., Professor, 工学部, 教授 (20069826)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAMI Satoshi lbaraki Univ., College of Eng., Research Associate, 工学部, 助手 (10261744)
TANABASHI Yoshihiko Nagasaki Univ., College of Eng., Professor, 工学部, 教授 (80039685)
KOMINE Hideo Ibaraki Univ., College of Eng., Assoc. Professor, 工学部, 助教授 (90334010)
HIRAO Takao Mitsui Chemical Products Co Ltd., Director, 土木資材部, 部長
MIYATA Yoshihisa National Defense Academy Lecturer, 講師
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| Project Period (FY) |
2000 – 2002
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| Keywords | Reinforcement / Geosynthetics / Upgrading / Sandwich earth structure / Cyclic loading / Embankment / 剛性 / 支持力 |
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| Research Abstract |
The present study aims at exploring a reinforcing method for upgrading earth structures under cyclic loading induced by traffic, ocean waves and earthquakes by using geocomposites which are manufactured by combining with two or three different kinds of geosynthetics. The keyword in this study is "Hybrid" and "Sandwich" which contains the following two aspects :
I) The material used in the study is a hybridized one in which the unwoven geosyntheitc is combined with the woven geosynthetic similar to the sandwich.
ii) Sand mat is placed at the both sides, above and beneath the geocomposite. This type can be called a hybrid-sandwich earth structure., In order to accomplish the advantageous aspects of the hybrid earth structure with the hybrid geosynthetic, model tests and numerical analysis were carried out. The following main findings were derived from the present study :
1) Sandwiched structures formed by sand mat placement in-between geosynthetics contribute to improvement of soft soils mo
… More
re markedly than in the case with sand mat only without geosynthetic reinforcement.
2) Sand mat placement combined with geosynthetics as a sandwich structure gives rise to improvement of permeability and transmssibity of geosynthetics. The geocomposite in which the woven geosynthetic is sandwiched by the woven geosynthetic in-getween is most suitable for accomplishing this purpose.
3) Advantages of sandwiched structures are recognized in the two aspects : the one is increase of stability of embankment and decrease in deformation and settlements of embankment.
4) The finite element computer code is formulated to consider the effect of confinement due to geosynthetics into deformation and stability of embankment with the sandwich structure.
5) Anew method combined by injecting cement mortar into send mat in the sandwich structure is suggested as a promising hybrid system for upgrading foundations and earth structures. In particular, this system is effective to increase stability and reduce settlements under cyclic loading induced by traffic ocean waves and earthquakes.
6) Either the use of geocomposite or the combination of non-woven geosynthetic with injection of cement mortar gives rise to stable reinforced revetments at the coastal area subjected to ocean wave actions. Less
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