1999 Fiscal Year Final Research Report Summary
Resarch on transition of dynamic failure of soils.
| Project/Area Number |
10450178
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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 | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Osaka University |
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Principal Investigator |
MATSUI Tamotsu Graduate school of Osaka University, Professor, 大学院・工学研究科, 教授 (20029143)
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| Co-Investigator(Kenkyū-buntansha) |
ODA Kazuhiro Graduate School of Osaka University, Research Associate, 大学院・工学研究科, 助手 (00185597)
TANAKA Yaso Kobe University, Research center for urban Safetyand Security, Professor, 都市安全研究センター, 教授 (40144597)
UCHIDA Kazunori Faculty of Agriculture., Kobe University, Professor, 農学部, 教授 (80111946)
NABESHIMA Yasuyuki Graduate School of Osaka University, Research Associate, 大学院・工学研究科, 助手 (40263214)
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| Project Period (FY) |
1998 – 1999
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| Keywords | dynamic failure mechanism / Liguifaction / Cyclic shear failure / intermediate soils / Plasticity Index / fine content / Clay minerals / Physical characteristics of soils |
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| Research Abstract |
Generally, in designing the civil engineering structures, engineers use the angle of internal friction f for sands or cohesion c for clays. Most of soils, however, have a various particle size distribution between sands and clays, which are called intermediate soils. They are dealt as clays taking into consideration safety of the structure. On the other hand, since the liquefaction took place for decomposed granite during Hyogoken-Nambu Earthquake in 1995, some researchers have investigated the cyclic behavior of the intermediate soils. However, their mechanical properties have not elucidated yet.
In this research project, a series of both static and cyclic triaxial tests in addition to cyclic torsional tests of the intermediate soils to investigate the relationship between static and cyclic behavior of the intermediate soils and soil properties. As the results, the static and cyclic strength decreases as clay content increases. Also, mineral composition of clay has an influence of the static and cyclic strength of the intermediate soils.
Also, the bender element tests during cyclic torsional tests were carried out in order to investigate the relationship between shear modulus degradation and soil properties of the intermediate soils. It was found that the shear modulus degrades sharply in the first 20 cycles during cyclic torsional test due to the increase of pore water pressure. The shear modulus degration decreases as the clay content increases.
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