2005 Fiscal Year Final Research Report Summary
Development of undisturbed sampling method using thick water-soluble polymer
| Project/Area Number |
16360235
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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 | National University Corporation Yokohama National University |
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Principal Investigator |
TANI Kazuo Yokohama National University, Faculty of Engineering, Professor, 大学院・工学研究院, 教授 (50313466)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Sampling / Undisturbed sample / Drilling / Polymer |
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| Research Abstract |
A new sampling method using thick water-soluble polymer was invented to obtain undisturbed samples from even difficult ground. The objectives of this study were to understand the characteristics of this method, to evaluate the polymer immersion effect, to allow this method for deep ground and to apply this method for down-hole triaxial test. The following conclusions were drawn.
1)Measurement of normal and shear stresses on the drill-core surface was made by the core barrel rotation experiments. The results revealed that, the shear stress was minimal while normal stress of several kilo Pascal's was recorded due to Wisenberg effect of the thick polymer. In addition, seepage tests were conducted to elucidate seepage characteristics of polymer into sand.
2)A series triaxial compression tests were conducted on sand specimen with polymer. The test results demonstrated that, there was practically no influence on the angle of internal friction whereas increase of the cohesion value was limited as no more than several kilo Pascal's.
3)A core barrel was developed for this polymer sampling from deep ground, and an attempt was made to obtain undisturbed samples from unconsolidated sand layers. Continuous drill cores of 100 millimeter diameter apparently with no sign of disturbance were obtained from 10 to 22 meters deep ground. Moreover, a larger diameter core barrel of 200 millimeter diameter was also successfully developed for the polymer sampling from non-uniform ground including large gravels or large pieces of sea shells.
4)A technique to prepare the test specimens for down-hole triaxial tests was developed utilizing this polymer sampling method. Trial attempts on mortar ground demonstrated that cylindrical specimens can be accurately drilled in the ground by this technique.
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[Journal Article] Development of new in-situ triaxial test apparatus using LVDT.2006
Author(s)
Ikenoya, T., Tsuru, T., Kaneko, S., Tachikawa, H., Tani, K.
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Journal Title
Proc.35th Domestic Symposium on Rock Mechanics, Jap.Soc.of Civil Engineers(in Japanese)
Pages: 145-148
Description
「研究成果報告書概要(欧文)」より
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