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Journal Articles

Evaluation of combined pre- and post-excavation grouting for reducing water inflow under high water pressure condition

Mikake, Shinichiro; Ikeda, Koki; Matsui, Hiroya; Tsuji, Masakuni*; Nishigaki, Makoto*

Doboku Gakkai Rombunshu, C (Chiken Kogaku) (Internet), 74(1), p.76 - 91, 2018/03

Pre-grouting of shafts and galleries had been conducted during the construction of MIU in the aspect of reducing water inflow. After excavating GL.-500m gallery, a post-grouting was performed on section of the pre-excavation grouting area under high water pressure condition (max: 4MPa). The post-grouting experiment was performed outside of the pre-grouting zone with designs, applying colloidal silica grouting material and complex dynamic grouting. It was estimated that the inflow after post-grouting was reduced by 1/100 of the case that pre- and post-grouting were not performed. These results indicate that the applied combined pre- and post-grouting methodology is effective in reducing water inflow and it can be applicable under high water pressure condition. Then, this paper states the theoretical evaluation of relationship between reduction of hydraulic conductivity and the grouting zone is very convenient and useful for grouting design and estimate of water inflow.

JAEA Reports

Studies on the reconstruction of the concept of rock mass around the tunnel; Japanese fiscal year, 2014 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Murakami, Hiroaki; Sasao, Eiji

JAEA-Research 2015-017, 54 Pages, 2015/12

JAEA-Research-2015-017.pdf:17.3MB

This report is concerned with research to reconstruct more realistic near-field (NF) concept for the geological disposal of radioactive waste. This year is the final year of this committee activities. So we have carried out the summary on Re-thinking of NF concept and its technical basis. Cooperation between the study fields and combination of various science and technology and evaluation methods are one of the important technical bases of NF concept. In addition, since the "Great East Japan Earthquake 2011", the safety paradigm has shifted dramatically. In the reconstruction of realistic NF concept, it is necessary to analyze what security matters whether society has become unacceptable for geological disposal. Committee, we also exchange views on such matters and presented the direction of future research and development for geological disposal.

JAEA Reports

Studies on the reconstruction of the concept of rock mass around the tunnel; Japanese fiscal year, 2013 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Ogata, Nobuhisa

JAEA-Research 2014-011, 43 Pages, 2014/09

JAEA-Research-2014-011.pdf:56.68MB

This report is concerned with research to reconstruct more realistic near-field (NF) concept for the geological disposal. In previous year, we examined the realistic concept for near-field, including rock mass around the tunnel, particularly based on the nuclide migration scenario. The time-series change of the field was divided into five stages of 0 to IV through the process of geological disposal (Excavation, Operation and Post-closure). Then at each respective stage, post-closure stage in particular; we examined interaction between environmental factors and exhaustive extraction of those factors affecting the near-field, focusing on each scale-time cross-section. In the reconstruction of realistic near-field concept, it is necessary to analyze security matters are unacceptable by society, regarding geological disposal. We also exchanged views on those matters and presented the future direction of research and development for geological disposal.

Journal Articles

Establishment of the theoretical evaluation of grouting zone with consideration of seepage forces

Mikake, Shinichiro; Nishigaki, Makoto*; Sato, Toshinori

Doboku Gakkai Rombunshu, C (Chiken Kogaku) (Internet), 70(1), p.33 - 43, 2014/01

This paper states establishment of the theoretical evaluation of the grouting zone during excavation of tunnel deep underground tunnel under high water pressure condition. In this study, relationship between allowable pressure and active pressure in the grouting zone is examined by means of one dimensional theoretical solution of pressure due to seepage forces act on the cross-section of the tunnel. The results indicate that allowable pressure is lower than active pressure under conditions of low cohesion. Furthermore, relationship between reduction of hydraulic conductivity and active pressure in the grouting zone is examined and it is confirmed that active pressure increases as hydraulic conductivity decreases by grout injection. Therefore, an accurate evaluation of the grouting zone is very important for grouting design based on the results obtained.

JAEA Reports

Studies on the reconstruction of the concept of rock mass around the tunnel; Fiscal year, 2012 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Aoki, Kenji*; Tochiyama, Osamu*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Yoshida, Hidekazu*; Ogata, Nobuhisa

JAEA-Research 2013-015, 21 Pages, 2013/11

JAEA-Research-2013-015.pdf:10.41MB

This report is concerned with research to reconstruct more realistic near-field concept for the geological disposal. In chapter, we examined the realistic concept for near field, including rock around the tunnel, based on the nuclide migration scenario in particular. The time-series change of the field was divided into five stages of 0$$sim$$IV through the process of geological disposal (Excavation, Operation and Post-closure). Then, for each stage respectively, we examined interaction between environmental factors and extraction of those factors changing the "field". The Goal of this year is to set up the state in the realistic "field" exhaustively, by focusing on the scale-time cross-section of each stage, especially post-closure stage, and to present the assignment of the next fiscal year.

Journal Articles

Research and development of radiation measuring instruments for lake,pond and river sediments, 1

Yanagizawa, Koichi; Hayashi, Toshio*; Oinuma, Masaru*; Takemori, Makoto*; Ishikawa, Takanori*; Okaya, Tomoichi*; Nishigaki, Makoto*

Shadan Hojin Butsuri Tansa Gakkai Dai-129-Kai (Heisei-25-Nendo Shuki) Gakujutsu Koenkai Koen Rombunshu, p.287 - 288, 2013/10

The development of instrument aimed at the measurement of radiation dose in the sediment of lakes, rivers and sea bed been carried out. The radiation level contained in the sediment at the bottom of lake and so on is anticipated to indicate the existence of locally high radiation spots where the diffused radioactive substance is accumulated in ponds, rivers and lakes by rainwater. The radiation dose measurement system this time is to measure $$gamma$$-ray by dragging the detector, which is called probe, at the bottom of lakes to understand the radiation dose over wide areas. Furthermore, the measurement of resistivity value at the bottom of lakes is simultaneously dose to presume the condition of sediment.

JAEA Reports

Developing the soil moisture sensor using optical fiber technique (Joint research)

Komatsu, Mitsuru*; Nishigaki, Makoto*; Seno, Shoji*; Hirata, Yoichi*; Takenobu, Kazuyoshi*; Tagishi, Hirotaka*; Kunimaru, Takanori; Maekawa, Keisuke; Yamamoto, Yoichi; Toida, Masaru*; et al.

JAEA-Research 2012-001, 77 Pages, 2012/09

JAEA-Research-2012-001.pdf:4.85MB

This research focused on methods of estimating the amounts of groundwater recharge, which are normally required as upper boundary conditions in groundwater flow analyses, based on measurements of infiltrating water in the ground, to systematize the methods and establish systems which are stable and measurable on site over a long time. Regarding developing measurement systems, fiber-optic strain measurement methods that enable multiple-point and long-distance measurement were used for measuring three quantities: suction pressure, soil moisture and volumetric water content rate obtained by applying water absorption swelling material, and each measurement was discussed. The results showed that the fiber-optic soil aquameter has two types of practical application: one for measuring suction pressure (Type I), and the other for measuring volumetric water content rate obtained by applying water absorption swelling material (Type III). Furthermore, by using measurement instruments in actual fields, the validity of the two methods for estimating the rainfall infiltration capacities of shallow-layer soils, that is, estimating the capacities either directly by measurements of soil water or from unsaturated hydraulic conductivities, was confirmed.

JAEA Reports

Interdisciplinary approach to improve and systematize the investigation and evaluation techniques on geological environment in relation to radioactive waste repository; Japanese fiscal year, 2010 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2011-033, 126 Pages, 2012/02

JAEA-Research-2011-033.pdf:31.33MB

The next advancements for the research of radioactive waste repository was started to improve and systematize the investigation and evaluation techniques on geological environment in consideration of intra-field of science and technology. Intra-field means the various fields among each study area of (a) geological environment, (b) design and engineering, (c) safety evaluation for radioactive waste repository, here. The following items were studied and discussed this year. (1) To Reconstruct Near Field (NF) Concept in consideration of coupled phenomena on geological environment. (2) To develop systematic investigation techniques on the geological environment in consideration of intra-field among each study area above mentioned (a), (b) and (c). Regarding (1), examination of NF concept focused on the realistic crystalline rock was carried out. Also through the overall discussion in the committee, comments from the all commissioners in relation to the intra-field of their study area were made to reflect on reconstruction of NF concept. Regarding (2), the research and development in consideration of NF and intra-field among each study area were conducted.

Journal Articles

Estimation of infiltration amount from in-situ moisture measuring method in shallow ground

Komatsu, Mitsuru*; Nishigaki, Makoto*; Seno, Shoji*; Toida, Masaru*; Tagishi, Hirotaka*; Takenobu, Kazuyoshi*; Yamamoto, Yoichi

Chikasui Jiban Kankyo Ni Kansuru Shimpojium 2011 Happyo Rombunshu (CD-ROM), p.17 - 26, 2011/11

no abstracts in English

JAEA Reports

Study on systemizing of technology for investigation and analysis of the deep underground geological environment; Japanese fiscal year, 2009 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2010-049, 282 Pages, 2011/02

JAEA-Research-2010-049.pdf:29.88MB

This report summarizes studies that have been carried out with the aim of assessing and systemizing the technology used for the investigation and analysis of the deep underground geological environment in relation to the disposal of radioactive waste. The main studies were: (1) a study on the research and development (R&D) topics proven to have practical application for the investigation, and analysis and understanding of the deep underground geological environment, and, (2) a study on leading edge technology that can provide the advanced technical basis for the investigation, analysis and understanding of the deep underground geological environment. Regarding the R&D topics (1, above), specific investigations, measurements, numerical analyses and chemical analyses were performed and reviewed with respect to the topics, (a) Repository design, engineering technology (b) Geological environment and (c) Safety evaluation. Based on the result of the review, topics requiring collaboration research in overlapping research fields, including safety assessment, were identified. Also, the near field concept (NFC) was reconsidered in terms of its realistic construction model. Regarding advanced technology (2, above), based on the objectives of the JAEA (Japan Atomic Energy Agency) research project, the study was implemented considering previous R&D results and detailed research result at the research site and thus an assessment of the need for advanced technical basis for investigation and analysis. This study contributed to the R&D development and its practical application.

JAEA Reports

Study on systemizing of technology for investigation and analysis of the deep underground geological environment; Japanese fiscal year 2008 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2009-055, 145 Pages, 2010/02

JAEA-Research-2009-055.pdf:55.53MB

This report summarizes studies that were carried out with the aim of assessing and systemizing the technology used for the investigation and analysis of the deep underground geological environment in relation to the disposal of radioactive waste. The main studies were: (1) a study on the research and development (R&D) topics proven to have practical application for the investigation, analysis and understanding of the deep underground geological environment, and, (2) a study on leading edge technology that can provide the advanced technical basis for the investigation, analysis and understanding of the deep underground geological environment. The principal results obtained from the studies are as follows: Regarding the R&D topics (1, above), the specific investigations, measurements, numerical and chemical analyses were reviewed with respect to engineering technology and the geological environment in this year. Based on the results of the review, topics requiring collaboration research in overlapping research fields, including safety assessment, were identified. Also, the near field concept (NFC) was reconsidered in terms of both the generic model and for crystalline rock. Regarding advanced technology (2, above), based on the objectives of the JAEA (Japan Atomic Energy Agency) research project, the study was implemented considering previous R&D results and detailed research result at the research site and thus an assessment of the need for advanced technical basis for investigation and analysis. This study contributed to the R&D development and its practical application.

Journal Articles

Applicability of countermeasure for reduction of groundwater inflow and construction of the Mizunami Underground Research Laboratory

Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Ishida, Hideaki; Nishigaki, Makoto*

Dai-54-Kai Jiban Kogaku Shimpojiumu Rombunshu, p.39 - 46, 2009/11

The Mizunami Underground Research Laboratory (MIU) is currently being constructed. During its construction, water inflow into the shafts of the MIU has been increasing and affecting the project progress. In order to reduce the water inflow into the shafts, borehole investigations and pre-excavation grouting have been conducted. The pre-excavation grouting has been undertaken at the predicted inflow area with existing method.

Journal Articles

Proposal of efficient pre-excavation grouting concept for deep underground rock excavation

Nobuto, Jun*; Mikake, Shinichiro; Nishigaki, Makoto*

Doboku Gakkai Rombunshu, C, 65(4), p.806 - 821, 2009/10

This paper describes a study on efficient pre-excavation grouting concept using cement grout for reducing water-inflow during excavation of crystalline rock in deep underground. Although thick grout mix is favorable for the efficiency of pre-excavation grouting, clogging phenomenon at the entrance of rock fractures in grout hole is concerned for thick grout mix. The influence of water-cement ratio on basic grout characteristics and clogging phenomenon is studied by laboratory experiment using cement grout with water-cement ratio of from 0.5 to 10.0. Finally, the efficient pre-excavation concept for the excavation of deep underground is proposed.

JAEA Reports

Study on systemizing technology on investigation and analysis of deep underground geological environment; Japanese fiscal year, 2007 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2008-099, 171 Pages, 2009/03

JAEA-Research-2008-099-1.pdf:28.65MB
JAEA-Research-2008-099-2.pdf:49.14MB

In this year, the following studies were carried out with the aim of systemizing the technology on the investigation and analysis to understand the deep underground geological environment in relation to the radioactive waste disposal. (1) The study on the research and development (R&D) subjects which turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis for the investigation and analysis of deep underground geological environment. The results obtained from the studies are as follows: Regarding (1), the specific investigations, measurements, numerical and chemical analyses were performed particularly for research subjects: (a) the repository design and engineering technology and (b) geological environment. Based on the results on (1), (c) tasks of collaboration research on niche area between the research fields, including the safety assessment field, were selected. Also subject's items of the NFC (Near Field Concept) redefinition were discussed. Regarding (2), based on the extraction tasks of JAEA (Japan Atomic Energy Agency) research project, the study was implemented with applying previous R&D results and detailed research at the research field was carried out. This study contributed to the R&D development for its practical application.

Journal Articles

Prevention of clogging phenomenon with high-grouting pressure

Nobuto, Jun*; Nishigaki, Makoto*; Mikake, Shinichiro; Kobayashi, Shinji*; Sato, Toshinori*

Doboku Gakkai Rombunshu (DVD-ROM), 64(4), p.813 - 832, 2008/12

This paper describes a study on grouting strategy for crystalline rock. First, grouting practices used in Nordic countries are summarized. Their main characteristics are the usage of thick slurry of grout material, dense pattern of grout holes and simultaneous injection of plural holes, which enable both of high-level water sealing and shortening of grouting work. To investigate the applicability of thick cement slurry, high-pressure clogging test simulating real grouting work has been conducted. The test results indicated the possibility to prevent the clogging phenomenon of thick cement slurry, i.e. water cement ratio of 1.6, by increasing the injection pressure gradually.

JAEA Reports

Study on systemizing technology on the investigation and analysis of deep underground geological environment; Japanese fiscal year, 2006 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2008-042, 236 Pages, 2008/04

JAEA-Research-2008-042.pdf:23.43MB

The following study was done with the aim of systemizing the technology on the investigation and analysis to grasp deep underground geological environment in relation to the radioactive waste disposal. (1) The study on the research and development (R&D) subjects which turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis of the investigation and analysis of deep underground geological environment. It continued in the former year and got the following results. Concerning (1), the concrete investigation, measurements, numerical analyses and chemical analyses were enforced about the following item and extracted some subjects with the viewpoint of radioactive waste disposal. Concerning (2), the evaluation of the results and a way to the practical use were discussed on the R&D activities of the following item. The R&D activities of the study group concerning (2) are related to the fundamental and elemental technology. It was discussed if these results could be taken into the practical investigation programs which characterize the geological environment and engineering technology in the Tono Geoscience Center. The Study group also discussed and gave the comment on the 2nd phase (the shaft construction phase of the MIU (Mizunami Underground Research Laboratory) research program in the JAEA.

JAEA Reports

Study on systemizing the technology on the investigation and analysis of deep underground geological environment; Japanese fiscal year, 2006 (Contract research)

Kojima, Keiji*; Onishi, Yuzo*; Watanabe, Kunio*; Nishigaki, Makoto*; Tosaka, Hiroyuki*; Shimada, Jun*; Aoki, Kenji*; Tochiyama, Osamu*; Yoshida, Hidekazu*; Ogata, Nobuhisa; et al.

JAEA-Research 2007-060, 210 Pages, 2007/09

JAEA-Research-2007-060-1.pdf:43.82MB
JAEA-Research-2007-060-2.pdf:41.2MB
JAEA-Research-2007-060-3.pdf:6.42MB

The following study was done with the aim of systemizing the technology on the investigation and analysis to grasp deep underground geological environment in relation to the radioactive waste disposal. (1) The study on the research and development (R&D) subjects which turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis of the investigation and analysis of deep underground geological environment. It continued in the former year and got the following results. Concerning (1), the concrete investigation, measurements, numerical analyses and chemical analyses were enforced about the following item and extracted some subjects with the viewpoint of radioactive waste disposal. More over, the way to make the co-operative program among each field of the following (a), (b) and (c) was discussed. (a) The subjects extracted with the viewpoint of the repository design and engineering technology. (b) The subject extracted with the viewpoint of the safety assessment. (c) The subjects extracted with the viewpoint of the geological environment. The joint research subjects among each field of (a), (b), (c) were also discussed. Concerning (2), the evaluation of the results and a way to the practical use were discussed on the R&D activities. The Study group also discussed and gave the comment on the 2nd stage of the MIU (Mizunami Underground Research Laboratory) research program in the JAEA.

Journal Articles

Study on filtration property of grouting materials; High-pressure filtration test

Nobuto, Jun*; Mikake, Shinichiro; Sato, Toshinori; Nishigaki, Makoto*; Larry Pax, C.*

Doboku Gakkai Heisei-19-Nendo Zenkoku Taikai Dai-62-Kai Nenji Gakujutsu Koenkai Koen Rombunshu, p.269 - 270, 2007/09

Authors are conducting research on method to achieve high-level water tightness in crystalline rock with suspension grout like cement slurry is studied. Grout should be infiltrated into very fine fractures to enhance the water tightness. For such fine fractures, the clogging phenomenon of grout material at the entrance of rock fractures tends to occur, and it results in insufficient infiltration of grout. Herein, laboratory experiment is conducted to investigate the clogging phenomenon using steel apparatus with fine slits simulating rock fracture. The results indicate clogging can be prevented to a significant level by increasing the injection pressure, although grout material accumulates over the slit.

Journal Articles

Grouting methodology in crystalline rock

Nobuto, Jun*; Kobayashi, Shinji*; Nishigaki, Makoto*; Mikake, Shinichiro; Sato, Toshinori

Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 8 Pages, 2007/04

Authors are conducting research on construction technologies such as water sealing measures as a scientific and technological basis for geological disposal. In this paper, the application patterns of grouting technology to excavation work in deep underground are selected first, and potential grouting material for each pattern is summarized. Next, the method to achieve high level water tightness in crystalline rock with suspension grout like cement and bentonite slurry is studied. Finally, focusing on pre-excavation grouting for horizontal tunnels, the effective injection method is studied.

Journal Articles

Progress of analysis methods of aquifer testing and recent technologies

Shinshi, Yoshihide*; Nishigaki, Makoto*; Takeuchi, Shinji

Tsuchi To Kiso, 54(5), p.6 - 9, 2006/05

no abstracts in English

34 (Records 1-20 displayed on this page)