2003 Fiscal Year Final Research Report Summary
Investigation and modeling of deformation structures on ground surface caused by fault rupturing
| Project/Area Number |
13450191
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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 | Yokohama National University |
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Principal Investigator |
TANI Kazuo Yokohama National University, Faculty of Engineering, Associate Professor, 工学研究院, 助教授 (50313466)
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| Co-Investigator(Kenkyū-buntansha) |
OHNAMI Masayuki Kozo Keikaku Engineering Inc., Numerical Analysis Section, Group Leader, 解析技術本部, グループリーダー
KANATANI Mamoru CRIEPI, Department of Earthquake Engineering, Senior Principal Researcher, 地盤耐震部, 上席研究員
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| Project Period (FY) |
2001 – 2003
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| Keywords | Fault rupture / Earthquake / Fault displacement / Incompetent surface layer |
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| Research Abstract |
In general, earthquake resistance design methods typically thke into account the structural failures by earthquake vibration and ground movements by liquefaction. However, serious fault rupture hazards on engineering structures were seen in Cokaeri earthquake, Turkey, and Chi-Chi earthquake, Taiwan, in 1999. Thus, this study focuses on mitigation technology for fault rupture hazards.
In 2001, a novel idea of mitigation measures was proposed that utilized the cushion effect of incompetent surface layer above active faults. Various forms of ground improvement methods were devised. This invention was patented claiming as a new ground improvement method, Application No.2001-316161.
In 2002, a series of physical model tests and numerical analyses were conducted. The results demonstrated that the improved ground comprised of an absorption layer and a rigid beam layer showed remarkable performance. Furthermore, flexural rigidity of the rigid beam layer and locations of anchors were proved to be some of the important design parameters.
In 2003, appropriate locations of anchors were investigated for dip-slip faults by the model tests. Design calculation method was also devised assuming the rigid beam layer as elastic beam resting on Whinkler's springs. Then, some trial calculations simulating the experimental results proved that this design model was adequate in predicting the behaviors of the improved ground. Finally, and attempt was made to calculate the prototype behavior assuming a railway truck crossing strike-slip fault. The computed results demonstrated that the proposed ground improvement method was effective in reducing the structural damages on the railway facilities significantly.
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