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Puebla, J.*; Hwang, Y.*; Maekawa, Sadamichi*; Otani, Yoshichika*
Applied Physics Letters, 120(22), p.220502_1 - 220502_9, 2022/05
Times Cited Count:20 Percentile:93.77(Physics, Applied)Funato, Takumi*; Matsuo, Mamoru
Physical Review Letters, 128(7), p.077201_1 - 077201_6, 2022/02
Times Cited Count:3 Percentile:56.47(Physics, Multidisciplinary)Funato, Takumi*; Matsuo, Mamoru
Physical Review B, 104(6), p.L060412_1 - L060412_5, 2021/08
Times Cited Count:3 Percentile:26.56(Materials Science, Multidisciplinary)Xu, M.*; Yamamoto, Kei; Puebla, J.*; Baumgaertl, K.*; Rana, B.*; Miura, Katsuya*; Takahashi, Hiromasa*; Grundler, D.*; Maekawa, Sadamichi*; Otani, Yoshichika*
Science Advances (Internet), 6(32), p.eabb1724_1 - eabb1724_4, 2020/08
Times Cited Count:88 Percentile:97.34(Multidisciplinary Sciences)Hioki, Tomosato*; Hashimoto, Yusuke*; Johansen, T. H.*; Saito, Eiji
Physical Review Applied (Internet), 11(6), p.061007_1 - 061007_5, 2019/06
Times Cited Count:7 Percentile:36.99(Physics, Applied)Kubota, Kenji*; Aoyagi, Kazuhei; Sugita, Yutaka
Proceedings of 2019 Rock Dynamics Summit in Okinawa (USB Flash Drive), p.729 - 733, 2019/05
During the excavation of shafts and galleries in the deep subsurface for disposing of high-level radioactive waste, an excavation disturbed zone (EdZ) or excavation damaged zone (EDZ) is developed around the shafts and galleries. Such zones could influence the transfer behavior of radioactive nuclides, and it is therefore important to understand the behavior of the EdZ or EDZ. We performed in situ experiments before, during, and after gallery excavation in galleries of 140 and 250 m in depth in an area of soft sedimentary rock in Japan. The results demonstrate that the extent of fractures induced by the gallery excavation related with EDZ was confined to about 0.45 m from the gallery wall in the 140 m gallery and to about 1 m from the gallery wall in the 250 m gallery. The extent of the unsaturated zone related with EdZ was about 1 m in the 140 m gallery, but an unsaturated zone did not appear in the 250 m gallery.
Kubota, Kenji*; Aoyagi, Kazuhei; Sugita, Yutaka
Koeki Shadan Hojin Butsuri Tansa Gakkai Dai-138-Kai (Heisei-30-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.51 - 54, 2018/05
In an excavation of shafts and galleries in the deep underground for disposing high level radioactive waste, an excavation disturbed zone (EdZ) or excavation damaged zone (EDZ) is developed around the shafts and galleries owing to the stress redistribution. It is important to understand the behavior of the EdZ or EDZ because these zone could have an effect on the transfer behavior of radioactive nuclide. Therefore, the authors performed the in situ experiment to investigate the behavior of EdZ or EDZ in the 140m and 250m gallery in the Horonobe Underground Research Laboratory. From the result of the experiments, the authors compared the characteristics of EdZ or EDZ between those in 140m and 250m gallery. The extent of the fractures induced by the gallery excavation, i.e., EDZ was about 0.45m in the 140m gallery and about 1m in the 250m gallery. The extent of the unsaturated zones related with EdZ was about 1m in the 140m gallery, however, unsaturated zone was not appeared in the 250m gallery.
Aoyagi, Kazuhei; Miyara, Nobukatsu; Ishii, Eiichi; Matsuzaki, Yoshiteru
Shigen, Sozai Koenshu (Internet), 5(1), 7 Pages, 2018/03
no abstracts in English
Aoyagi, Kazuhei; Nago, Makito*
Jiban Kogakkai-Shi, 65(8), p.12 - 15, 2017/08
In this paper, we described the development of the supporting tool of observational construction of the underground research laboratory, and the monitoring result of hydro-mechanical properties around the gallery wall. As an observational construction tool, we developed a "3D geological structure/construction data visualization system". The geological data, measurement data, construction data, and prediction analysis results are visualized and integrated comprehensively as the construction proceeds. The planned support pattern was examined according to the visualized data. In addition, the Excavation Damaged Zone (EDZ) was extended within 1.0 m from the gallery wall. In this area, hydraulic conductivity was enhanced. However, the extent of the EDZ was not enlarged along with time; the stability of the support was also confirmed on the basis of the measurement of stress in the shotcrete. Integrating these results the observational construction considering the development of an EDZ can be established. This technology will have an important role in geological disposal of high-level radioactive waste.
Takachi, Kazuhiko; Taniguchi, Wataru
JNC TN8400 99-042, 68 Pages, 1999/11
The buffer material is expected to maintain its low water permeability, self-sealing properties, radionuclides adsorption and retardation properties, thermal conductivity, chemical buffering properties, overpack supporting properties, stress buffering properties, etc. over a long period of time. Natural clay is mentioned as a material that can relatively satisfy above. Among the kinds of natural clay, bentonite when compacted is superior because (1)it has exceptionally low water permeability and properties to control the movement of water in buffer, (2)it fills void spaces in the buffer and fractures in the host rock as it swells upon water uptake, (3)it has the ability to exchange cations and to adsorb cationic radioelements. In order to confirm these functions for the purpose of safety assessment, it is necessary to evaluate buffer properties through laboratory tests and engineering-scale tests, and to make assessments based on the ranges in the data obtained. This report describes the procedures, test conditions, results and examinations on the buffer material of dynamic triaxial tests, measurement of elastic wave velocity and liquefaction tests that aim at getting hold of dynamic mechanical properties. MWe can get hold of dependency on the shearing strain of the shearing modulus and hysteresis damping constant, the application for the mechanical model etc. by dynamic triaxial tests, the acceptability of maximum shearing modulus obtained from dynamic triaxial tests etc. by measurement of elastic wave velocity and dynamic strength caused by cyclic stress etc. by liquefaction tests.
Mitsui, Takaya
KEK Proceedings 97-14, p.255 - 278, 1997/11
no abstracts in English
Yoneda, Yoshihiro*; Takahara, Hiroyuki*; Nakamura, Naoaki*; Akiyama, Shinsuke*; Moriya, Toshifumi*; Negi, Tateyuki*
PNC TJ1380 97-001, 1338 Pages, 1997/03
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