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JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory; FY2009-2010 (Contract research)

Ijiri, Yuji*; Noda, Masaru*; Nobuto, Jun*; Matsui, Hiroya; Mikake, Shinichiro; Hashizume, Shigeru

JAEA-Technology 2013-047, 819 Pages, 2014/03

JAEA-Technology-2013-047-01.pdf:41.49MB
JAEA-Technology-2013-047-02.pdf:25.26MB

The researches on engineering technology in the Mizunami Underground Research Laboratory plan consists of (1) research on engineering technology at a deep underground, and (2) research on engineering technology as abasis of geological disposal. The former research mainly aimed in this study are categorized in (a) development of design and construction planning technologies, (b) development of construction technology, (c) development of countermeasure technology, (d) development of technology for security. In this study, the researches on engineering technology are proceeded in these four categories by using data measured down to GL-460m during construction as a part of the second phase of the MIU plan.

JAEA Reports

Development of grout materials for a geological disposal system for high-level radioactive waste, 2

Kawaguchi, Masanao; Nakanishi, Tatsuro; Kishi, Hirokazu; Nobuto, Jun*; Yamada, Tsutomu*; Fujita, Tomo; Hatanaka, Koichiro

JAEA-Data/Code 2012-007, 250 Pages, 2012/11

JAEA-Data-Code-2012-007.pdf:20.55MB

Cementitious materials are commonly used for rock support, lining, and grouting, their pH plume are considered to have an adverse effect on long-term safety of a geological disposal system. In addition, during the emplacement of waste package with buffer material, it is required to limit amount of groundwater inflow to a certain level by grouting. Therefore, it is necessary to develop new grout materials with penetrability for smaller fractures. We have developed new grout materials, which have better penetrability and are environmentally more friendly than exinting cementitious grout materials since FY 2007. This sequel report shows the most appropriate composition and the penetration characteristic of new grout materials to be suitable for the ${it in-situ}$ experiment based on the result of indoor test carried out after FY 2008.

Journal Articles

Fundamental study on a grout penetration model for a HLW repository

Fujita, Tomo; Shinkai, Fumiaki*; Nobuto, Jun*

Journal of Energy and Power Engineering, 6(8), p.1191 - 1203, 2012/08

This study aims at validating applicability of the theoretical formula by Gustafson and Still to analysis of permeation behavior of Bingham fluid into a one-dimensional micro-fissure by comparing analysis results with laboratory tests data conducted using bentonite slurry as a Bingham fluid. The results showed that the calculation values by Gustafson and Stille model agreed well with values of laboratory penetration test.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory; FY2008 (Contract research)

Ijiri, Yuji*; Noda, Masaru*; Sasakura, Takeshi*; Nobuto, Jun*; Matsui, Hiroya; Mikake, Shinichiro; Hashizume, Shigeru

JAEA-Technology 2012-018, 288 Pages, 2012/07

JAEA-Technology-2012-018.pdf:19.13MB

The researches on engineering technology in the Mizunami Underground Research Laboratory plan consists of (1) research on engineering technology at a deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research mainly aimed in this study are categorized in (a) development of design and construction planning technologies, (b) development of construction technology, (c) development of countermeasure technology, (d) development of technology for security. In this study, the researches on engineering technology are proceeded in these four categories by using data measured down to GL-300m during construction as a part of the second phase of the MIU plan.

Journal Articles

Characteristic evaluation of colloidal silica grout material developed for a high level radioactive waste geological repository

Kishi, Hirokazu; Kawaguchi, Masanao; Naito, Morimasa; Hatanaka, Koichiro; Nobuto, Jun*; Sugiyama, Hirokazu*

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 19(1), p.3 - 8, 2012/06

To reduce amount of groundwater inflow into a geological repository, the grouting is expected to play a very important role because the geological environment in Japan is often characterized by many fractures and abundant groundwater. Basically, cementitious materials are used for grouting, however the resulting highly alkaline plume released from the materials could influence the long-term performance of barrier system as a consequence of alteration of both the buffer material and the host rock. To minimize such effects, JAEA has carried out research and development on three types of grout material with low-pH performance that decreases influence in the alteration. This paper focuses on the Colloidal silica grout, and presents its unique characteristics obtained from laboratory tests on pH, viscosity, leaching and so on. The results indicate that the grout has good performances in pH and viscosity. It is concluded that the grout can be greatly used for the repository.

Journal Articles

Grouting experiment with colloidal silica at 300 m depth of the Mizunami URL

Kobayashi, Shinji*; Nobuto, Jun*; Sugiyama, Hirokazu*; Kusano, Takashi*; Tsuji, Masakuni*; Mikake, Shinichiro; Matsui, Hiroya

Proceedings of European Rock Mechanics Symposium (EUROCK 2012) (CD-ROM), 13 Pages, 2012/05

JAEA (Japan Atomic Energy Agency) has been conducting geoscientific research and development at underground research laboratory under construction, in crystalline rock at Mizunami, Gifu. Considering water treatment expense, the water inflow should be minimized. Although cement grout has been applied to reduce the inflow at 460 m depth at the MIU (Mizunami Underground Research Laboratory), water inflow through narrow fractures which cement grout cannot penetrate might be a problem at deeper underground. Colloidal silica grout, which is liquid-type grout, has high durability as well as good penetrability and is therefore tested at a depth of 300 m. The results indicated that liquid-type grout could sufficiently reduce the hydraulic conductivity of rock mass with less than 1 Lu. In the water pressure resistance test, the ultra-high-pressure packer was set in the pilot hole. The results indicated that liquid-type grout could keep sealing effect even under high water pressures over 9 MPa.

Journal Articles

Analysis and numerical simulation of seismic events recorded in the ventilation shaft at the Mizunami URL

Niimi, Katsuyuki*; Kobayashi, Shinji*; Nobuto, Jun*; Matsui, Hiroya; Yamamoto, Masaru

Proceedings of European Rock Mechanics Symposium (EUROCK 2012) (CD-ROM), 13 Pages, 2012/05

JAEA has been conducting geoscientific research and development at underground research laboratories under construction in Japan. In this study, frequency and wave propagation characteristics were analyzed using seismic records for six earthquakes obtained with the seismometers in URL. It was found that seismic motions were amplified from the deep underground to the shallow surface and that the wave propagation characteristics were different in NS and EW directions. It was also assumed that the recorded data of the seismometer on the ground might be influenced by aboveground structures. Then, numerical simulations using SHAKE, which is commonly used for seismic response analysis in Japan and had been applied to the earthquake resistance design in Phase I, were carried out to compare analytical results and observed records. The results showed that the calculated results agreed well with those observed when epicenters are close.

Journal Articles

Development of grout injection model to single fracture in considering inertia term and its application on parallel plate experiments

Kishida, Kiyoshi*; Kobayashi, Kenichiro*; Hosoda, Takashi*; Fujita, Tomo; Kishi, Hirokazu; Kuzuha, Yuji; Nobuto, Jun*

Zairyo, 61(3), p.245 - 252, 2012/03

In this research work, the grout injection model of single fracture, in which non-Newtonian fluid and the inertia term are considered, has been developed. Then, the grout injection experiments of single fracture have been conducted and the numerical simulations have been also carried out. As compared our proposed model with past one, the remarkable difference in grout penetration could not be clearly observed. On the other hand, the difference in pressure at aperture entrance and penetration velocity of the grout could be clearly observed. Our proposed model could show the practical behavior against previous model. Moreover, it can be also confirmed that viscosity of grout material through the material experiments are differed with that through the parallel plate injection experiments.

Journal Articles

The Project for grouting development for high level radioactive waste repository, 2; Laboratory experiment on penetrability of grout material

Kawaguchi, Masanao; Kishi, Hirokazu; Nobuto, Jun*; Sugiyama, Hirokazu*

Doboku Gakkai Heisei-23-Nendo Zenkoku Taikai Dai-66-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.67 - 68, 2011/09

no abstracts in English

Journal Articles

The Project for grouting development for high level radioactive waste repository, 9; Theoretical discussion on fracture flow of grout material in considering sinusoidal rough wall

Kishida, Kiyoshi*; Kobayashi, Kenichiro*; Hosoda, Takashi*; Kuzuha, Yuji; Kishi, Hirokazu; Nobuto, Jun*

Doboku Gakkai Heisei-23-Nendo Zenkoku Taikai Dai-66-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.81 - 82, 2011/09

no abstracts in English

Journal Articles

Pre-excavation grouting with micro-fine cement below four hundreds meter depth

Ishii, Yoji; Mikake, Shinichiro; Kamiya, Akira; Watanabe, Kazuhiko; Nobuto, Jun*; Kusano, Takashi*

Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.185 - 190, 2011/01

The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the Ventilation Shaft. A region with high hydraulic head and low hydraulic conductivity was intersected by the pilot borehole at around GL-400m during these investigations. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the ventilation shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.

Journal Articles

Test execution of liquid-type grout at depth of 300m of Mizunami Underground Research Laboratory

Nobuto, Jun*; Tsuji, Masakuni*; Kusano, Takashi*; Mikake, Shinichiro; Kamiya, Akira; Ishii, Yoji

Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.179 - 184, 2011/01

At Mizunami Underground Research Laboratory, the water inflow should be minimized, considering water treatment expense. Although cement grout has been applied to reduce water inflow up to 460 m depth, water inflow through small fractures which cement grout cannot penetrate can not be neglected at deeper underground. Liquid-type grout which has high durability as well as good penetrability was therefore tested at the depth of 300 m. Test results indicated that liquid-type grout could sufficiently reduce hydraulic conductivity of rock mass with less than 1Lu, and could keep improvement effect even after applied water pressure of more than 9 MPa was applied.

Journal Articles

The Project for grouting development for the high level radioactive waste repository, 6; Analysis of the in-situ grouting test results using Gustafson and Stille model

Tsuji, Masakuni*; Nobuto, Jun*; Okihara, Mitsunobu*; Sugita, Yutaka; Fujita, Tomo; Shinkai, Fumiaki

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.93 - 94, 2010/09

no abstracts in English

Journal Articles

The Project for grouting development for the high level radioactive waste repository, 3; Durability test of coloidal silica grout

Sugiyama, Hirokazu*; Nobuto, Jun*; Fukuoka, Naomi; Shinkai, Fumiaki; Shimada, Shunsuke*; Koyama, Tadao*; Kijima, Masashi*; Terashima, Rei*

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.87 - 88, 2010/09

no abstracts in English

JAEA Reports

Development of grout materials for a geological disposal system for high-level radioactive waste

Fukuoka, Naomi; Shinkai, Fumiaki; Miura, Norihiko*; Nobuto, Jun*; Yamada, Tsutomu*; Naito, Morimasa

JAEA-Data/Code 2010-005, 353 Pages, 2010/07

JAEA-Data-Code-2010-005-01.pdf:8.91MB
JAEA-Data-Code-2010-005-02.pdf:46.47MB

High-level radioactive waste management in Japan is based on the multi-barrier concept, composed of the engineered barrier system and the surrounding geological formations. Although cementitious materials are commonly used for rock support, lining, and grouting, their pH plume are considered to have an adverse effect on long-term safety of a geological disposal system. In addition, during the emplacement of waste package with buffer material, it is required to limit amount of groundwater inflow into a disposal pit or tunnel to a certain level by grouting because the bentonite clay buffer is easy to swell in time by contact with the groundwater. Therefore, it is necessary to develop new grout materials with penetrability for smaller fractures. This report shows the most appropriate composition of new grout materials to be suitable for the in-situ experiment based on the result of indoor test.

Journal Articles

Staus of the Mizunami URL construction and study on engineering technology

Matsui, Hiroya; Noda, Masaru*; Nobuto, Jun*

Proceedings of ITA-AITES 2011 World Tunnel Congress/37th General Assembly (USB Flash Drive), 8 Pages, 2010/05

JAEA has been conducting research and development at two underground research laboratory projects in crystalline and sedimentary rock respectively. The MIzunami Underground Research Laboratory project (MIU) is the URL being constructed in crystalline rock for geoscientific research and development. The MIU has two shafts, the Main and ventilation shafts, with horizontal drifts between the shafts. Niches were also excavated for geoscientific research at several depths. The depth of the main and ventilation shafts reached G.L.-460 m in November, 2010. The objective of the study on engineering technology was the demonstration of existing engineering technology and any needed improvements for the design, construction and operation of a deep underground structure. The study is on going and it was divided into four subjects, which are demonstration of design methodology, existing and supplementary excavation methods, countermeasures during excavation and safe construction.

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

Studies on engineering technologies in the Mizunami Underground Research Laboratory; FY2007 (Contract research)

Noda, Masaru*; Suyama, Yasuhiro*; Nobuto, Jun*; Ijiri, Yuji*; Mikake, Shinichiro; Matsui, Hiroya

JAEA-Technology 2009-009, 194 Pages, 2009/07

JAEA-Technology-2009-009.pdf:44.14MB

In construction phase in MIU, the study on engineering technology consist of following four subjects, which are Demonstration of design methodology of a greatly deepr underground structure, Demonstration of excavation and supplymentary methods of a greatly deepr underground structure, Demonstration of the countermeasure during excavation of a greatly deepr underground structure and Demonstration of the safe construction for a greatly deepr underground structure. In the study in FY2007, the design methodlogy in Phase 1 is verified until 200 m depth on excavation of ventilation shaft. A plan, countermeasure and concept for influence of differential water pressure, long-term maintenance and risk management in the view of geological disposal project were proposed.

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.

Journal Articles

Pre-excavation grouting in construction of Mizunami Underground Research Laboratory

Hara, Masato; Kinoshita, Harunobu; Ikeda, Koki; Yamamoto, Masaru; Nobuto, Jun*

Tonneru Kogaku Hokokushu (CD-ROM), 18, p.23 - 30, 2008/11

In the excavation for the ventilation shaft of the Mizunami Underground Research Laboratory, pre-excavation grouting with ordinary Portland cement is conducted to reduce the water inflow. The target value for the hydraulic conductivity of grouted zone is set to be 2 Lugion, considering mainly the capacity of water treatment facility. In this paper, the grouting work conducted up to the depth of GL. -220m is summarized. By reviewing the water inflow and hardened cement injected into rock fractures observed at shaft wall, the validity of grouting method so far is evaluated.

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