1991 Fiscal Year Final Research Report Summary
Soft Soil Improvement by Vertical Sand piles
| Project/Area Number |
02555110
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
基礎・土質工学
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| Research Institution | Nagoya University |
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Principal Investigator |
MATSUO Minoru Nagoya University, Engineering, Professor, 工学部, 教授 (40025937)
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| Co-Investigator(Kenkyū-buntansha) |
KANATANI Yoshihisa Chubu Electric Power Co., Environment Division, Engineer, 立地環境本部, 副本部長
OHTSUKA Satoru Nagoya University, Engineering, Associate professor, 工学部, 助教授 (40194203)
ASAOKA Akira Nagoya University, Engineering, Professor, 工学部, 教授 (50093175)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Bearing capacity / Consolidation / Elastic-Plastic / Sand pile / Vertical drain / Soil improvement / Permeability |
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| Research Abstract |
Sand Drains
(1)The range of soil permeability which yields the variation of partial drain behavior was found
10^<-7>cm/sec k 10^<-4>cm/sec
when a clay deposit of about 25 meters thick is considered.
(2)When soil permeability lies on this particular range the bigger the load intensity, the more the partial drain effect should be expected.
(3)The efficiency of sand drains is to be observed in a limited range of soil permeability and under a particular magnitude of load intensity.
2. Sand Compaction Piles
(1)The bearing capacity of soft clay with vertical sand compaction piles is extremely influenced by the stiffness of applied load. When load application through a rigid
footing is considered fully drained/swelling conditions for sand piles provide bigger
bearing capacity than undrained/no swelling conditions. On the other hand, when
flexible load application such as embankment loading is the case, undrained conditions
give bigger bearing capacity than fully drained/swelling condition.
(2)The increase of the undrained strength of clay due to displacement and consolidation by sand pile installation should be correctly evaluated when relatively low sand replacement ratio is considered.
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