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Hotta, Akitoshi*; Morita, Akinobu*; Kajimoto, Mitsuhiro*; Maruyama, Yu
Nihon Genshiryoku Gakkai Wabun Rombunshi, 16(3), p.139 - 152, 2017/09
Tokiwa, Tetsuya; Asamori, Koichi; Hiraga, Naoto*; Yamada, Osamu; Moriya, Hirokazu*; Hotta, Hikaru*; Kitamura, Itaru*; Yokota, Hideharu
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.117 - 122, 2010/10
In this paper, we discuss the relationship between the accurate hypocentral distribution and 3-D geological structure in and around the Horonobe area, Japan. We carried out multiplet-clustering analysis by using data of the 421 micro-earthquakes which occurred from 1st September, 2003 to 30th September, 2007. The 3-D geological structure model was mainly constructed from previous seismic reflection profiles and drilling data. As a result of this analysis, although there are some differences in depth between them, the hypocenters are distributed in NNW-SSE direction and become deeper from the west toward the east. The distributed pattern of the hypocenters is similar to the one of the geological structure. These results indicate that the hypocentral distribution may represent existence of active zone related to the geological structure, and provide effective information which can contribute to establishing methods for estimating the future evolution of the geological environment.
Goke, Mitsuo*; Horita, Masakuni*; Wakabayashi, Naruki*; Nakaya, Atsushi*
JNC TJ7400 2005-058, 167 Pages, 2005/03
JNC-TJ7400-2005-058.pdf:7.49MB
The purposes of this study were to contribute to both the evaluation of mechanical stability of a research drift and the plan of future studies. The crack tensor model based on mechanical property on the Toki granite at the Mizunami Underground Research Laboratory construction site was applied to analyze the rock stress as a research drift and a shaft were excavated. The virtual fracture model was applied to the hydraulic conductivity change analysis.The results are as follows:1)In the reference case of a shaft, convergence showed 9.03mm at the GL-500m, and 21.78mm at the GL-1000m. The maximum increase rate of hydraulic conductivity showed about 14 times at the both depth. In the reference case of a drift, convergence of a splingline showed 3.36mm at the GL-500m, and 7.99mm at the GL-1000m. The maximum increase rate of hydraulic conductivity showed a range of about 28 times from about 19 times at the GL-500m, and a range of about 45 times from about 15 times at the GL-1000m.2)As rock class getting weaker, the convergence of a shaft and a drift increased, also the stress in support parts increased, while distributions of the safety factor and the hydraulic conductivity change were almost changeless.3)As the direction of a drift changed to 90 degrees form 0 degrees, the convergence of a shaft and a drift increased, also the stress in support parts increased, and distributions of the safety factor and the hydraulic conductivity change were affected.4)As compared with analytical result regardless of excavation damaged zone, analytical result in consideration of excavation damaged zone showed that the convergence and the stress in support parts increased. Especially, the maximum increase rate of hydraulic conductivity increased remarkably. For example, the maximum increase rate of hydraulic conductivity was 240 times to 400 times at the bottom of a drift
Hotta, Hikaru*
JNC TJ5410 2005-004, 111 Pages, 2005/03
JNC-TJ5410-2005-004.pdf:19.25MB
We have compiled seismic data obtained by JNC seismographic station and JMA (Japan Meteorological Agency) Hi-net stations including Wakkanai-kita, Wakkanai-higashi, Wakkanai-nishi, Sarufutu-kita, Sarufutu-minami, Hamatonbetu, Horonobe, Toyotomi, Nakatonbetu, Teshio, Otoineppu and Nakagawa station from December 20th, 2002 to September 30th, 2004 in and around the Horonobe area. In that period, 1,618 earthquakes were recorded by JMA stations in the area. 103 events out of them were recorded at least two JNC seismographic stations and were able to detect the arrival time of P-and S-wave. In this study, the hypocenters were calculated by hypomh and cross-spectruma method on the basis of JMA and JNC data. Cross-spectruma method is higher precise than hypomh method. As a result of cross- spectruma analysis, we could identify the 7 groups of hypocenter areas in and around the Horonobe area. It is examined that the relationship between the hypocenter information and geological structures based on hypocenter areas, existing topographical and geological features.
Goke, Mitsuo*; Horita, Masakuni*; Tada, Hiroyuki*
JNC TJ7400 2004-007, 102 Pages, 2004/02
JNC-TJ7400-2004-007.pdf:4.85MB
Tono Geoscience Center (TGC), Japan Nuclear Cycle Development Institute (JNC) conducts the Mizunami Underground Research Laboratory (MIU) project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques in the deep underground application. The purposes of this work were to contribute to the rock mechanical modeling for MIU project. We proposed an analytical method of modeling of excavation damaged zone. The crack tensor analytical model was applied to analyze the rock stress in consideration of the existence of excavation damaged zone as a research drift and a shaft were excavated. The virtual fracture model was applied to the hydraulic conductivity change analysis.The results are as follows:1) As compared with analytical result without excavation damaged zone, the crack tensor stress analysis in consideration of excavation damaged zone showed that the convergence of a shaft and a drift increased and the maximum value of principal stress decreased, while the safety factor distribution was almost changeless.2) As compared with analytical result without excavation damaged zone, the hydraulic conductivity change analysis in consideration of excavation damaged zone showed the maximum increase rate of hydraulic conductivity increased remarkably.3) As the stiffness decreased in excavation damaged zone, the convergence of a shaft and a drift increased, the maximum value of principal stress decreased, and the maximum increase rate of hydraulic conductivity increased. Especially, in analytical case supposed that new cracks parallel to perimeter of a drift broke out in excavation damaged zone, the maximum increase rate of hydraulic conductivity was up to 5000 times.4) As the stiffness of rock mass decreased by taking into the existence of excavation damaged zone, the convergence reduction effect increased, and the stress in support parts increased.
Goke, Mitsuo*; Tada, Hiroyuki*; Horita, Masakuni*; Wakabayashi, Naruki*
JNC TJ7400 2003-003, 93 Pages, 2003/02
JNC-TJ7400-2003-003.pdf:5.87MB
Tono Geoscience Center (TGC), Japan Nuclear Cycle Development Institute (JNC) conducts the Mizunami Undergroud Research Laboratory (MIU) project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques in the deep underground application. The purposes of this study were to contribute to the construction of rock mechanical modeling for MIU project. The virtual fracture model based on mechanical property on the Toki granite was applied to the 2-D hydraulic conductivity change analysis in excavating a research drift and a shaft. The crack tensor analysis model was introduced to the stress analysis before the hydraulic conductivity change analysis. The results are as follows: (1) The crack tensor stress analysis showed very small displacement on the perimeter of a shaft and a drift in intact rock mass, while large displacement appeared in fault zone. (2) More than 10 times large hydraulic conductivity from the initial one appeared in the extent of 1m from the perimeter of a drift and a shaft, in the hydraulic conductivity change analysis with the virtual fracture model for the intact rock mass. The maximum increase of hydraulic conductivity was up to 100 times from initial one. The fault zone showed more than 10 times larger hydraulic conductivity in the extent of 4m from the perimeter. (3) The extent of hydraulic conductivity change was affected by the direction of a drift due to the direction of fractures and the initial stress condition. For example, the rate of hydraulic conductivity increased from initial one changed 110 times to 670 times with the direction of a drift, at the side wall of a drift at the depth of 945m. (4) There was no clear effect to reduce the displacement by supports in the drift in intact rock mass.
Tanai, Kenji; Horita, M.*; Dewa, Katsuyuki*; Goke, Mitsuo*
JNC TN8410 2001-026, 116 Pages, 2002/03
JNC-TN8410-2001-026.pdf:9.19MB
Earthquake resistance for the underground structure is higher than the ground structure. Therefore, the case of examining the earthquake resistance of underground structure was little. However, it carries out the research on the aseismic designing method of underground structure, since the tunnel was struck by Hyogo-ken Nanbu Earthquake, and it has obtained a much knowledge. However, an object of the most study was behavior at earthquake of the comparatively shallow underground structure in the alluvial plain board, and it not carry out the examination on behavior at earthquake of underground structure in the deep rock mass. In the meantime, underground disposal facility of the high level radioactive waste constructs in the deep underground, and it carries out the operation in these tunnels. In addition, it has made almost the general process of including from the construction start to the backfilling to be about 60 years (Japan Nuclear Fuel Cycle Development Institute, 1999). During these periods, it is necessary to also consider the earthquake resistance as underground structure from the viewpoint of the safety of facilities. Then, it extracted future problem as one of the improvement of the basis information for the decision of the safety standard and guideline of the country on earthquake-resistant design of the underground disposal facility, while it carried out investigation and arrangement of earthquake-resistant design cases, guidelines and analysis method on existing underground structure, etc.. And, the research item for the earthquake resistance assessment of underground structure as case study of the underground research laboratory.
Tanai, Kenji; Iwasa, Kengo; Hasegawa, Hiroshi; Goke, Mitsuo*; Horita, Masakuni*; Noda, Masaru*
JNC TN8400 99-044, 140 Pages, 1999/11
This report consists of three items: (1)Study of the repository configuration, (2)Study of the surface facilities configuration for construction, operation and buckfilling, (3)Planning schedule, In the repository configuration, the basic factors influencing the design of the repository configuration are presented, and the results of studies of various possible repository configurations are presented for both hard and soft rock systems. Here, the minimum conditions regarding geological environment required to guide design are assumed, because it is difficult to determine the repository configuration without considering specific conditions of a disposal site. In the surface facility configuration, it is illustrated based on the results of construction, operation, buckfilling studies for underground disposal facility and EIS report of CANADA. In the schedule, the overall schedule corresponding to the repository layout is outlined in link with the milestone of disposal schedule set forth in the government's basic policy. The assumptions and the basic conditions are summarized to examine the General Schedule from start of construction to closure of a repository. This summaly is based on the technologies to be used for construction, operation and closure of a repository. The basic national policies form the framework for this review of the general schedule.
*; Shibanuma, Kiyoshi; Kakudate, Satoshi; *; *; Hotta, Masataka*; Oka, Kiyoshi; Tada, Eisuke; Munakata, Tadashi*; Honda, Keizo*; et al.
JAERI-M 93-066, 133 Pages, 1993/03
no abstracts in English
Horita, M.*; Furuichi, Mitsuaki*; Ito, K.*; Sudo, Ken*
PNC TJ7449 91-001VOL2, 406 Pages, 1991/05
PNC-TJ7449-91-001VOL2.pdf:11.33MB
no abstracts in English
Horita, M.*; Furuichi, Mitsuaki*; Ito, K.*; Sudo, Ken*
PNC TJ7449 91-001VOL1, 406 Pages, 1991/05
PNC-TJ7449-91-001VOL1.pdf:3.51MB
no abstracts in English
; *; Hotta, Hiroshi;
Bulletin of the Chemical Society of Japan, 49(3), p.600 - 605, 1976/03
Times Cited Count：23no abstracts in English
; *; Hotta, Hiroshi;
Int.J.Appl.Radiat.Isot., 26(12), p.726 - 730, 1975/12
no abstracts in English
; *; Hotta, Hiroshi;
Bulletin of the Chemical Society of Japan, 47(7), p.2158 - 2163, 1975/07
no abstracts in English
Hotta, Hiroshi; ; ; ; ;
JAERI-M 5775, 25 Pages, 1974/07
no abstracts in English
Onuki, Akira; Tamai, Hidesada; Yoshida, Hiroyuki; Shibata, Mitsuhiko; Akimoto, Hajime; Chitose, Hiromasa*; Hotta, Akitoshi*; Fujimura, Ken*
no journal, ,
no abstracts in English
Moriya, Hirokazu*; Niizato, Tadafumi; Kitamura, Itaru*; Hotta, Hikaru*; Ohara, Hidefumi
no journal, ,
The source locations of earthquakes at the Horonobe area, north of Hokkaido, Japan have been relocated by using the multiplet-clustering analysis (MCA) to identify the subsurface structures and to reveal the mechanism of earthquakes. The absolute source locations of 221 earthquakes were determined by the "hypomh" algorithm to find the overall structures in this area. After that, those earthquakes were classified into 10 groups of multiplets which are the groups of events with very similar waveforms and their source locations have been relocated based on the MCA in order to reveal the fine scale structures. The multiplet-clustering analysis has revealed that the earthquake locations show the structures trending from NS to NNE-SSW with reverse or strike-slip focal mechanism.
Chitose, Hiromasa*; Hotta, Akitoshi*; Onuki, Akira; Tamai, Hidesada; Yoshida, Hiroyuki; Shibata, Mitsuhiko; Akimoto, Hajime; Fujimura, Ken*
no journal, ,
no abstracts in English
Tamai, Hidesada; Onuki, Akira; Shibata, Mitsuhiko; Akimoto, Hajime; Chitose, Hiromasa*; Hotta, Akitoshi*; Fujimura, Ken*
no journal, ,
no abstracts in English
