Kansai Geotechnology And Environment Res Center

Settsu, Japan

Kansai Geotechnology And Environment Res Center

Settsu, Japan
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Hioki K.,Osaka Institute of Technology | Hattori K.,Kansai Geotechnology And Environment Res Center | Sawa K.,Kansai Geotechnology And Environment Res Center | Nakayama Y.,Kansai Geotechnology And Environment Res Center | Inazumi S.,Akashi National College of Technology
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2016

In this study, an analysis was made of the causes of variations in the results of Particle size distribution test (sedimentation analysis), liquid limit test, plastic limit test and unconfined compression test in which the coefficient of variation was nearly 5% or higher during proficiency testing of geomaterial tests. The analysis was made based on the results of a questionnaire survey conducted at the same time as the proficiency testing. As a result, it was verified that not only the experience of test engineers but also complying with standards, and checking, inspecting and correcting test apparatuses and measuring instruments are important to the improvement of the accuracy of geomaterial tests. It was also revealed that the maximum and minimum weights measured by a balance scale affect test accuracy. ©2016 The Society of Materials Science.


Hioki K.,Osaka Institute of Technology | Iwanaga S.,Chuo Fukken Consultants Co. | Hashimoto A.,Kansai Geotechnology And Environment Res Center | Murakami S.,Fudo Tetra Corporation
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014

In this study, Hydraulic conductivity tests using a flexible wall permeameter were conducted using the improved soils by deep mixing method. The effects of whether measures are taken or not to prevent leakage through sidewalls on the results of permeability tests, and the condition that satisfied the condition of hydraulic conductivity k not exceeding 1.0 × 10 -9m/s were investigated. As a result, it was verified that 1) taking measures to prevent the leakage through sidewalls is essential when conducting a flexible wall permeability test using the improved soils by deep mixing method and that 2) a correlation was recognized between the hydraulic conductivity k and unconfined compression strength qu of the improved soils by deep mixing method and k never exceeds 1.0 × 10-9m/s if q u is 2.0MN/m2 or higher. © 2014 The Society of Materials Science.


Sawa K.,Kansai Geotechnology And Environment Res Center | Nakayama Y.,Kansai Geotechnology And Environment Res Center | Kusumoto N.,Kansai Geotechnology And Environment Res Center | Nakata Y.,Kansai Geotechnology And Environment Res Center
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014

When the strength of earth is so low that the earth is not able to maintain the upper structure, soil improvement methods such as cement mixing are generally recommended. In an unconfined compression test for deciding cement volume and confirming the strength of soil improvement, the mean value of test results of three samples are generally used, although the dispersion of the three test results are left out of consideration. Recently, the estimation method of dispersion for test results is discussed internationally and the notation of dispersion is united under the term "uncertainty", which is used in many fields of industry, medicine, agriculture and so on. As the Japanese Industrial Standard, the estimation methods of uncertainty are necessary to testing and calibration laboratories. In this thesis, firstly the estimation method of the uncertainty of compression test results of cement mixing soil is presented by the analyses of verification experiments on causes of dispersion. Next, it makes clear that the uncertainty of test results is able to be estimated by the proficiency test that evaluates the test result of a laboratory in comparison with results of many laboratories. The uncertainties of the two methods above show that the measuring equipment and testing apparatus do not affect uncertainty, and the influence of the operator (laboratory) and the difference of samples are conversely large. © 2014 The Society of Materials Science.

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