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Okutsu, Kazuo*; Morikawa, Seiji*; Shimbo, Hiroshi*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Murakami, Takeshi*; Aoyama, Yuji*
JNC TJ8400 2005-013, 117 Pages, 2005/02
JNC-TJ8400-2005-013.pdf:3.24MB
To integrate the system for evaluation of long-term hydraulic condition in near field of TRU waste disposal, the engineered barrier, which consists of bentonite buffer and cementitious materials, was employed in the series of laboratory tests. On the bentonite buffer, with the aim of investigating of the effect of (i) interlayer cation in bentonite, (ii) content of siliceous sand and (iii) the ionic strength of ground water on its mechanical and hydraulic properties, series of laboratory tests were conducted. The same lot of bentonite was used in the series of tests to obtain consistent data. In addition, the swelling test of the laminated bentonite with caliumization front was conducted for verification of the proposed constitutive model. On cementitious materials, the altered specimen that produced immersing was investigated the water permeation and also characteristics. The hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated.
Okutsu, Kazuo*; Morikawa, Seiji*; Shimbo, Hiroshi*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Murakami, Takeshi*; Aoyama, Yuji*
JNC TJ8400 2005-012, 272 Pages, 2005/02
JNC-TJ8400-2005-012.pdf:7.05MB
To integrate the system for evaluation of long-term hydraulic condition in near field of TRU waste disposal, the engineered barrier, which consists of bentonite buffer and cementitious materials, was employed in the series of laboratory tests.On the bentonite buffer, with the aim of investigating of the effect of (i)interlayer cation in bentonite, (ii)content of siliceous sand and (iii)the ionic strength of ground water on its mechanical and hydraulic properties, series of laboratory tests were conducted. The same lot of bentonite was used in the series of tests to obtain consistent data. In addition, the swelling test of the laminated bentonite with caliumization front was conducted for verification of the proposed constitutive model.On cementitious materials, the altered specimen that produced immersing was investigated the water permeation and also characteristics. The hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated.
Okutsu, Kazuo*; Morikawa, Seiji*; Taguchi, Katsunori*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Takase, Hiroyasu*; Aoyama, Yuji*
JNC TJ8400 2003-087, 199 Pages, 2004/02
JNC-TJ8400-2003-087.pdf:4.82MB
The system development for evaluating the long-term alteration of hydraulic field in near field was examined. The "Evidential Support Logic" for ensuring the long-term stability of the repository was developed and evaluated. Furthermore, the developed chemical/mechanical alteration action analysis system was verified and improved. The system was coupled for the long-term alteration evaluation analysis.
Okutsu, Kazuo*; Morikawa, Seiji*; Taguchi, Katsunori*; Kuroyanagi, Mikio*; Sahara, Fumihiro*; Takase, Hiroyasu*; Aoyama, Yuji*
JNC TJ8400 2003-086, 426 Pages, 2004/02
JNC-TJ8400-2003-086.pdf:11.01MB
The system development for evaluating the long-term alteration of hydraulic field in near field was examined. The "Evidential Support Logic" for ensuring the long-term stability of the repository was developed and evaluated. Furthermore, the developed chemical/mechanical alteration analysis system was verified and improved. The system was coupled for the long-term alteration evaluation analysis.
Sasakura, Takeshi*; Kuroyanagi, Mikio*; Okamoto, Michitaka*; Kobayashi, Ichizo*
JNC TJ8400 2003-048, 180 Pages, 2003/02
JNC-TJ8400-2003-048.pdf:9.43MB
Series of laboratory tests were conducted to investigate the effect of 1)cation exchange of Na-bentonite for Ca ion, and 2)the swelling behavior of bentonite, on its mechanical and hydraulic properties.
Sasakura, Takeshi*; Kuroyanagi, Mikio*;
JNC TJ8400 2002-025, 182 Pages, 2002/02
JNC-TJ8400-2002-025.pdf:10.59MB
To integrate the system for evaluation of long-term hydraulic condition in near field of TRU waste disposal, series of laboratory tests were conducted to investigate the effect of (a)cation exchange of Na-bentonite for Ca ion, and (b)the swelling behavior of bentonite, on its mechanical and hydraulic properties. For the purpose of this study, same lot of bentonite was used in a series of tests to obtain consistent data. A constitutive model of clayey materials, called Cam-clay model, was expanded conceptually to express the effects mentioned above. The research results of this year are summarized below; (1)Some basic properties such as cation exchange capacity, particle density, grain size distribution, compaction-characteristics and water content were obtained. To examine the effect of previous swelling history of bentonite on its swelling characteristics and hydraulic and mechanical properties, specimens, which generated swelling deformation to various volumetric strain levels, were specially prepared and used in the following tests. Swelling pressure tests, swelling deformation tests, permeability tests were conducted to observe one dimensional swelling characteristics and hydraulic properties of Na-bentonite and Ca-bentonite. High-pressured triaxial consolidated-undrained (CU) compression tests and high-pressured consolidation tests were also carried out to investigate the compression, swelling, and shearing behavior of each type of bentonite. (2)As indicated in previous studies, two important phenomena (a)bentonite possesses remarkable swelling capacity, (b)cation exchange of Na-bentonite for Ca-ion lead increasing of hydraulic conductivity, were confirmed in the test results. From the swelling deformation test results and published data, it was found that swelling capacity of bentonite has no dependency on previous swelling history and it could be easily expressed as a function of void ratio e. It was also confirmed that swelling pressure and water ...