| Project/Area Number |
10450176
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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 | University of Tokyo |
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Principal Investigator |
KOSEKI Junichi Institute of Industrial Science, Univ.of Tokyo, Associate Professor, 生産技術研究所, 助教授 (30272511)
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| Co-Investigator(Kenkyū-buntansha) |
HAYANO Kimitoshi Institute of Industrial Science, Univ.of Tokyo, Research Associate, 生産技術研究所, 助手 (40302632)
SATO Takeshi Institute of Industrial Science, Univ.of Tokyo, Research Associate, 生産技術研究所, 助手 (30092224)
TATSUOKA Fumio Department of Civil Engineering, Univ.of Tokyo, Professor, 大学院・工学系研究科, 教授 (70111565)
KOHATA Yukihiro Muroran Institute of Technology, Associate Professor, 工学部, 助教授 (90215301)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,700,000 (Direct Cost: ¥12,700,000)
Fiscal Year 2000: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1999: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 1998: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Course grained soil / Triaxial test / Hollow cylindrical torsional test / Deformation property / Local deformation measurement / Cyclic loading / Young's modulus / Shear modulus / ポアソン比 / 締固め / 拘束圧 |
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| Research Abstract |
In order to investigate and model the mechanical behavior of course grained soils under a variety of stress states with different stress histories, two series of triaxial tests were conducted on rectangular specimen (with cross-section of 23^*23 cm and height of 58 cm) of densely compacted gravel. Based on results from a series of cyclic triaxial tests following different stress paths under several levels of confining stress, a unique relationship between modified stress and strain parameters during monotonic loading was proposed. By combining this relationship with newly modified hysteresis laws, it was demonstrated that the proposed model could reasonably simulate the cyclic behaviors of dense gravel. Based on results from another series of triaxial tests, their creep behaviors were found to be not negligible, with considerable effects of change in the strain rate on the monotonic loading properties.
Studies were also made on the elastic wave velocities of sands and gravel. On Toyoura
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sand, primary wave velocities measured with small accelerometers that were set on the side surface of rectangular specimen were found to be consistent with the static Young's moduli evaluated by applying small amplitude cyclic loading. On gravel with larger particle size, however, the wave velocities were much higher than the statically evaluated values, due possibly to the effects of inhomogeneity in the structure of soil particles.
In addition, a large scale true-triaxial apparatus equipped with a pair of horizontal loading plates and a medium scale triaxial and torsional shear apparatus equipped with a local deformation measurement system for hollow cylindrical specimen (with outer diamete of 20 cm, inner diameter of 16 cm and height of 30 cm) were newly introduced. Based on results from preliminary tests, their accuracy in controlling and measuring stresses and strains was confirmed.
These apparatuses enabled to make comprehensive studies on anisotropy of deformation properties in the vertical and horizontal directions and their changes due to rotation of principal stress direction. Less
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