Grant-in-Aid for Co-operative Research (A)
|Allocation Type||Single-year Grants |
|Research Institution||Tokai, University |
HAMADA Masanori Tokai Univ., School of Marine Science and Technology, Professor, 海洋学部, 教授 (30164916)
NODA Shigeru Tottori Univ., Faculty of Engineering, Associate Professor, 工学部, 助教授 (80135532)
TOWHATA Ikuo Tokyo Univ., Faculty of Civil Engineering, Associate Professor, 工学部, 助教授 (20155500)
KITAHARA Michihiro Tokai Univ., School of Marine Science and Technology, Associate Professor, 海洋学部, 助教授 (60135522)
WAKAMATSU Kazue Waseda Univ., Science and Engineering Laboratory, Research Associate, 理工学研究所, 特別研究員 (10132789)
YASUDA Susumu Kyushu Institute of Technology, Faculty of Civil Engineering, Associate Professo, 工学部, 助教授 (90192385)
小管 晋 東海大学, 海洋学部, 助教授 (60056158)
福江 正治 東海大学, 海洋学部, 助教授 (40119699)
星谷 勝 武蔵工業大学, 工学部, 教授 (30061518)
|Project Period (FY)
1989 – 1991
Completed (Fiscal Year 1991)
|Budget Amount *help
¥13,000,000 (Direct Cost: ¥13,000,000)
Fiscal Year 1991: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1989: ¥6,800,000 (Direct Cost: ¥6,800,000)
|Keywords||Liquefaction / Permanent Ground Displacement / Waterfront / Reclaimed Ground / Lifeline / Earthquake Hazard Prevention / Foundation Piles / Buried Pipes / 地震動の増幅 / 海底地盤 / すべり / 津波 / 埋立地 / 海底地すべり / 親水護岸|
The summary of the results of the present research is as follows ;
(i) It was pointed out based on the state of the art on lifeline performance in reclaimed ground during past earthquakes that specific research subjects such as earthquake motion in the neighborhood of fault, dynamic response of soft ground, liquefaction-induced ground displacement and its effect on buried lifeline facilities should be proceeded to create earthquake-proof urban societies in waterfronts in Japan.
(ii) Liquefaction can cause several kinds of damage to lifeline structures ; settlement and tilting of structures due to reduction of bearing capacity of ground, floating of buried structures due to the buoyancy of the liquefied soil, collapse of quay walls and retaining walls due to earth pressure increase, failure of earth structures like embankment, and damage to liquefaction-induced large ground displacement.
(iii) The liquefaction-induced ground displacements were found during ten past earthquakes in Japan as
well as in United States. The ground displacements were oriented from sand dunes and natural levees with a little higher elevation towards old streams of big rivers with a lower elevation. The maximum ground displacement reached over 12 m during the 1964 Niigata earthquake.
(iv) The magnitude of the ground displacement has a close correlation with the thickness of the liquefied layer, but not with the gradient of the ground surface. The mechanism of the occurrence of the liquefaction-related large ground displacement has not been clarified. Therefore, more studies on case histories of ground displacement, numerical analyses, experimental studies are required.
(v) The liquefaction-induced ground displacement caused severe damage to buried structures such as foundation piles and pipelines. It was conjectured from examination of damaged structures and experimental studies that a drag force of liquefied soil was applied to the buried structures.
(vi) A method to prevent liquefaction-induced ground displacement, where flexible inground walls are constructed in liquefiable soil, was proposed and its effectiveness was verified by shaking table tests. Less