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Journal Articles

Dislocation densities and intergranular stresses of plastically deformed austenitic steels

Tomota, Yo*; Ojima, Mayumi*; Harjo, S.; Gong, W.*; Sato, Shigeo*; Ung$'a$r, T.*

Materials Science & Engineering A, 743, p.32 - 39, 2019/01

 Times Cited Count:19 Percentile:85.18(Nanoscience & Nanotechnology)

Journal Articles

A Study of methods to prevent piping and erosion in buffer materials intended for a vertical deposition hole at the Horonobe Underground Research Laboratory

Jo, Mayumi*; Ono, Makoto*; Nakayama, Masashi; Asano, Hidekazu*; Ishii, Tomoko*

Geological Society Special Publications, 482, 16 Pages, 2018/09

 Times Cited Count:1 Percentile:17.46

Journal Articles

High stereographic resolution texture and residual stress evaluation using time-of-flight neutron diffraction

Xu, P. G.; Harjo, S.; Ojima, Mayumi*; Suzuki, Hiroshi; Ito, Takayoshi*; Gong, W.; Vogel, S. C.*; Inoue, Junya*; Tomota, Yo*; Aizawa, Kazuya; et al.

Journal of Applied Crystallography, 51(3), p.746 - 760, 2018/06

AA2018-0163.pdf:3.0MB

 Times Cited Count:18 Percentile:90.21(Chemistry, Multidisciplinary)

Journal Articles

An Investigation on mechanical properties of in-situ rock mass at the Horonobe Underground Research Laboratory

Tsusaka, Kimikazu*; Inagaki, Daisuke*; Niunoya, Sumio*; Jo, Mayumi*

Proceedings of 8th Asian Rock Mechanics Symposium (ARMS-8) (USB Flash Drive), 9 Pages, 2014/10

Journal Articles

Long-term behaviors of a tuunel in a sedimentary soft rock due to fluid-mechanical interaction

Aoki, Tomoyuki*; Sanada, Hiroyuki; Jo, Mayumi*; Yamamoto, Takuya*; Matsui, Hiroya

Dai-12-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.709 - 716, 2008/09

Long-term behaviors of a tunnel at great depth in sedimentary soft rocks are investigated based on pore fluid-mechanical interaction. Poroelastic parameters of diatomaceous and siliceous mudstones at the Horonobe URL site are determined from the tests proposed in this study using a triaxial test apparatus. The test procedures with their theoretical base are described. Coupled fluid-mechanical behaviors on circular and horse-shoe-shaped tunnels supported with shotcrete are numerically analyzed based on the theory of poroelasticity. Some long-term behaviors of rocks and supports peculiar to the fluid-mechanical interaction differing from creep behavior are found from the analysis results.

Journal Articles

Consideration on poroelastic behavior of siliceous rock mass around an opening by stress-seepage coupled analysis

Sanada, Hiroyuki; Matsui, Hiroya; Yamamoto, Takuya*; Aoki, Tomoyuki*; Ogawa, Toyokazu*; Jo, Mayumi*; Fujii, Yoshiaki*

Heisei-19-Nendo Shigen, Sozai Gakkai Hokkaido Shibu Sokai Oyobi Shunki Koenkai Koen Yoshishu, p.9 - 10, 2007/06

Japan Atomic Energy Agency has been conducting the Horonobe Underground Reseach Laboratory Project as a part of geological isolation research and development at Horonobe-town in Hokkaido, Japan. The rocks around URL have high porosity and low permeability. Therefore, the excess pore pressure caused by URL excavation is possible to affect to the stability of surrounding rock. In this point of view, the authors carried out a stress-seepage coupled analysis to understand the process of the pore pressure change due to excavation and the influence to the stability of surrounding rock and support system. As a result, the large excess pore pressure causes a part in surrounding rock on excavation in an anisotropic initial stress condition and it dissipates with time. The pore pressure change causes the complex deformation in the surrounding rock as well. However, the phenomena are not significant influence to the stability of the surrounding rock and support system.

Journal Articles

Stability analysis of underground opening during excavation, taking time-dependent behaviour of surrounding rock mass into consideration

Ogawa, Toyokazu*; Aoki, Tomoyuki*; Jo, Mayumi*; Matsui, Hiroya; Horii, Hideyuki*

Dai-36-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu, p.39 - 44, 2007/01

In case rock exhibits time-dependent deformation, it is important to evaluate this effect on the tunnel stability, since the rock deforms elastically as well as inelatically even at the time of excavation. This paper introduces an engineering approach method to explain the effect of time-dependent deformation of rock at tunnel excavation stages on the stability. The mechanical parameters to describe a Burgers type rheological model are determined, based upon the drained triaxial creep test results performed on mudstone samples. With the parameters determined, plane-strain 2 dimensional numerical analyses are subsequently performed. In the analysis a couple of indices to describe the degree and timing of time-dependent deformation are introduced with reference to the instantaneous elastic deformation, and their effects on the amount of deformation and support pressure subsequent to the support erection are investigated.

JAEA Reports

Investigation on time-dependent behavior of sedimentary rock (Phase 3)

Yamamoto, Takuya*; Aoki, Tomoyuki*; Jo, Mayumi*

JNC TJ5400 2005-002, 200 Pages, 2005/03

JNC-TJ5400-2005-002.pdf:42.65MB

For the rational design of the underground facility and for the safety during construction and operation it is necessary to consider the long-term stability of the rock mass around a drift. Especially, the time-dependent behavior of sedimentary rock is important because the mechanism of time-dipenednt is not well understood. Here, laboratory tests of rock specimens collected from the borehole investigation and numerical analysis on the stability of the rock mass around a drift were discussed for last two years. In this year, additional laboratory tests were performed to confirm the several important knowledges for last two years. Moreover, the preliminary numerical analysis was carried out to predict the EDZ due to excavation of underground facility.

JAEA Reports

Investigation on time-depedent behavior of sedimentary rock, 2

Yamamoto, Takuya*; Aoki, Tomoyuki*; Taki, Haruo*; Jo, Mayumi*

JNC TJ5400 2003-005, 190 Pages, 2004/02

JNC-TJ5400-2003-005.pdf:37.41MB

none

JAEA Reports

Investigation on time-dependent behavior of sedimentary rock

Yamamoto, Takuya*; Aoki, Tomoyuki*; Taki, Haruo*; Jo, Mayumi*

JNC TJ5400 2003-001, 120 Pages, 2003/06

JNC-TJ5400-2003-001.pdf:14.04MB

none

JAEA Reports

None

Shimo, Michito*; Yamamoto, Hajime*; Jo, Mayumi*; Yamagami, Masahito*; Fumimura, Kenichi*; Kumamoto, So*; Igarashi, Takafumi*

JNC TJ7440 2005-083, 991 Pages, 2003/01

JNC-TJ7440-2005-083.PDF:130.74MB

None

JAEA Reports

Investigation on time-depedent behavior of sedimentary rock, 2

Yamamoto, Takuya*; Aoki, Tomoyuki*; Taki, Haruo*; Jo, Mayumi*

JNC TJ5400 2003-004, 73 Pages, 2000/02

JNC-TJ5400-2003-004.pdf:8.3MB

none

Oral presentation

Factors affecting leaching behavior of nitrogen species from diatomaceous mudstone

Ueda, Takahiro*; Hokora, Hideyuki*; Igarashi, Toshifumi*; Jo, Mayumi*; Sataka, Hiroyuki

no journal, , 

Horonobe Underground Research Center, located in northern Hokkaido, Japan, has been excavating shafts of an underground research facility to establish general techniques for the assessment of deep geological environment. In this site, the groundwater seepage from the shafts and leachate from the waste rock storage site contain high concentrations of total nitrogen. Ammonium-nitrogen (NH$$_{4}$$-N), the major nitrogen species in the seepage and leachate, has been removed by a nearby treatment facility. However, NH$$_{4}$$-N is easily oxidized to nitrite-nitrogen (NO$$_{2}$$-N) and nitrate-nitrogen (NO$$_{3}$$-N) by nitrification in the excavated rock storage site, which makes the removal process employed on site less effective. Therefore, column experiments that simulated the infiltration of rainwater through the storage site were carried out to understand the phenomena and the factors affecting the leaching behavior of nitrogen species and nitrification, and to propose countermeasures for preventing nitrification. The results showed that the nitrification was inhibited when the rock layer was almost saturated, and that this process was temperature dependent. These indicate that nitrification can be mitigated by controlling hydrological conditions like water saturation.

Oral presentation

Reducing the amount of leaching water, boron and nitrogen of excavated soil by the covering sheet

Kato, Kinya*; Itabashi, Hideharu; Sataka, Hiroyuki; Jo, Mayumi*

no journal, , 

no abstracts in English

Oral presentation

Factors affecting the leaching of nitrogen species from diatomaceous mudstone

Igarashi, Toshifumi*; Ueda, Takahiro*; Hokora, Hideyuki*; Jo, Mayumi*; Kudo, Hajime

no journal, , 

Horonobe Underground Research Center, located in northern Hokkaido, Japan, has been excavating shafts and drifts of an underground research facility to establish general techniques for the assessment of deep geological environment. In this site, the groundwater seepage from the shafts and drifts as well as leachate from the excavated rock storage site contain high concentrations of total nitrogen. Ammonium-nitrogen (NH$$_{4}$$-N), the major nitrogen species in the seepage and leachate, has been removed by a nearby treatment facility. However, NH$$_{4}$$-N is easily oxidized to nitrite-nitrogen (NO$$_{2}$$-N) and nitrate-nitrogen (NO$$_{3}$$-N) by nitrification in the excavated rock storage site, which makes the removal process employed on site less effective. Therefore, column experiments that simulated the infiltration of rainwater through the storage site were carried out to understand the leaching and nitrification of nitrogen species and the factors affecting the phenomena. The results showed that the nitrification was inhibited when the rock layer was almost saturated, and that this process was temperature dependent. These indicate that nitrification can be mitigated by controlling hydrological conditions like water saturation.

Oral presentation

Oral presentation

Oral presentation

The In-situ experiment for verification of performance of engineered barrier system in Horonobe Underground Research Laboratory, 9; Application of low alkaline cement for concrete plug

Nakayama, Masashi; Miura, Norihiko*; Ishida, Tomoko*; Takeda, Nobufumi*; Niunoya, Sumio*; Jo, Mayumi*

no journal, , 

no abstracts in English

Oral presentation

The In-situ experiment for verification of performance of engineered barrier system in Horonobe Underground Research Laboratory, 7; Development drilling machine for large-diameter disposal pit

Niunoya, Sumio*; Shimohara, Masahiro*; Jo, Mayumi*; Nago, Makito*; Nakayama, Masashi; Tanai, Kenji; Hashimoto, Yuta; Nejigane, Nobuto

no journal, , 

no abstracts in English

30 (Records 1-20 displayed on this page)