Grant-in-Aid for Scientific Research (A)
|Allocation Type||Single-year Grants|
|Research Institution||Hiroshima University|
TSUCHIDA Takashi Hiroshima University, Graduate School of Engineering, Professor, 大学院工学系研究科, 教授 (10344318)
HIBINO Tadashi Graduate School of Engineering, Associate Professor, 大学院工学系研究科, 助教授 (50263736)
WATABE Yoichi Port and Airport Research Institute, Head of Soil Mechanics Division, 地盤構造部, 土質研究室長 (00371758)
OTSUBO Masami Kyusyu University, Graduate School of Bioresource and Bioenvironmental Sciences, Professor, 大学院農学研究院生産環境科学部門, 教授 (80112316)
加納 誠二 広島大学, 大学院・工学研究科, 助手 (40280408)
佐々木 康 広島大学, 大学院・工学研究科, 教授 (90274109)
五明 美智男 東亜建設工業株式会社, 技術研究所・水理環境研究室, 室長
関本 恒浩 五洋建設株式会社, 技術研究所, 開発課長(研究職)
|Project Period (FY)
2003 – 2006
Completed(Fiscal Year 2006)
|Budget Amount *help
¥29,510,000 (Direct Cost : ¥22,700,000、Indirect Cost : ¥6,810,000)
Fiscal Year 2006 : ¥1,950,000 (Direct Cost : ¥1,500,000、Indirect Cost : ¥450,000)
Fiscal Year 2005 : ¥5,720,000 (Direct Cost : ¥4,400,000、Indirect Cost : ¥1,320,000)
Fiscal Year 2004 : ¥8,840,000 (Direct Cost : ¥6,800,000、Indirect Cost : ¥2,040,000)
Fiscal Year 2003 : ¥13,000,000 (Direct Cost : ¥10,000,000、Indirect Cost : ¥3,000,000)
|Keywords||sedimentation environment / aging effect / marine clay / consolidation / seabed / tidal flat / wave / 粘土 / せん断 / セメンテーション / 海底地盤 / 沈降 / 温度効果|
The purpose of this study is to find a relationship between the environments of soil sedimentation and the engineering properties of the ground. The findings of the study are summarized as follow:
(1) The process of floc formation and its settling and sedimentation has an important role for the large void ratio structure of natural clay.
(2) By adding small amount of cement to clay slurry, the structure of large void ratio structure of aged clays could be reproduced in the laboratory.
(3) Sedimentation and consolidation tests of marine clay were carried out under flowing water condition. When the water flow was large, the height of the clay decreased with stair-like pattern due to repeat of the erosion and the consolidation. The shear strength of the clay consolidated under flowing water was larger than that consolidated under the stationary water condition.
(4) When soft bottom mud with high water content over the liquid limit is fluidized by the pressure induced by waves, cracks are generated in the surface of the mud. The cracks develop under the action of tensile stress and shear stress caused by the rotation of principal stress in the periodic motion of waves. The mechanism of the acceleration of consolidation of the mud by wave action is elucidated through experimental and numerical studies.
(5) When sandy soil containing 10% fines was subjected to the cyclic water pressure change, it was observed that the fines moved to the upper direction in the soil and finally reached to the surface. The upward movement of fines took place when the water pressure decreased and large excess pore pressure was observed at the ground surface. It was suggested that the occurrence of liquefaction under the cyclic water pressure change was closely related to the upward movement of fines.