Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2015); Development of design and construction planning and countermeasure technologies (Contract research)

Toguri, Satohito*; Kobayashi, Shinji*; Tsuji, Masakuni*; Yahagi, Ryoji*; Yamada, Toshiko*; Matsui, Hiroya; Sato, Toshinori; Mikake, Shinichiro; Aoyagi, Yoshiaki

JAEA-Technology 2017-005, 43 Pages, 2017/03

JAEA-Technology-2017-005.pdf:4.4MB

The study on engineering technology in the Mizunami Underground Research Laboratory (MIU) project roughly consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration and mitigating of the excavation effect. In FY2015, as a part of the important issues on the research program, water-tight grouting method has been developed. Grouting methods utilized in the MIU were evaluated and the post-excavation grouting at the -500m Access/Research Gallery-South was planned based on these evaluation results. Also, technology development from the viewpoint of geological disposal was summarized, and information on the alternative method to the grouting method was collected and organized.

Post-grouting with colloidal silica at great depth of the Mizunami Underground Research Laboratory, Japan

Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro; Matsui, Hiroya

Proceedings of 8th Nordic Grouting Symposium, p.171 - 185, 2016/09

This paper presents the application of a durable liquid-type colloidal silica grout (CSG), to the great depth of the Mizunami Underground Research Laboratory (MIU). The CSG had been invented decades ago in Japan for the purpose of the ground improvement. A post-grouting experiment with the CSG carried out in 300 m depth of MIU confirmed its applicability and good durability at a great depth more than 3 years. Furthermore, a comparison study of applying the CSG between this experiment and a Swedish project indicated good applicability of the Swedish theoretical design to MIU. The CSG with the Swedish design were applied to the post-grouting campaign in a gallery at 500 m depth for further reducing water ingress and for developing the latest grouting methodology. The grouting was successful in reducing the abundant inflow from the rock with many fractures. The conductivity of the grouted rock mass of the latter fans is estimated to be lower than 10 m/s.

Post-excavation grouting new design, results and evaluation of a gallery at great depth in Mizunami Underground Research Laboratory

Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro

Dai-44-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.359 - 364, 2016/01

Pre-excavation grouting of shafts and galleries has been conducted during the construction of Mizunami Underground Research Laboratory in the aspect of safe works and reducing the discharge treatment of the water inflow. The grouting methodology has been simultaneously studied and developed as there is less experience of grouting in low conductive rock with high water pressure, especially in Japan. After excavating GL.-500m gallery on the ventilation shaft side, a post-excavation grouting campaign was performed on a 16-meter section of the pre-grouted area. Three new options for the grouting design were adopted and found to be effective with sufficiently decreasing the water inflow into the gallery.

Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2013); Development of design and construction planning and countermeasure technologies (Contract research)

Kobayashi, Shinji*; Niimi, Katsuyuki*; Okihara, Mitsunobu*; Tsuji, Masakuni*; Yamada, Toshiko*; Sato, Toshinori; Mikake, Shinichiro; Horiuchi, Yasuharu*; Aoyagi, Yoshiaki

JAEA-Technology 2014-035, 172 Pages, 2015/01

JAEA-Technology-2014-035.pdf:91.27MB

The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration or reversal and mitigating of the excavation effect. To develop design and construction planning technologies, and countermeasure technology, the analysis of measured data during earthquake and seismic movement characteristics at deep underground, and the examination of grouting method were carried out. The knowledge of the seismic movements at deep underground was obtained by which observation records of seismometers at Mizunami underground research laboratory were analyzed to verify the earthquake-resistant design of the shafts and tunnels. As for" Study on grouting method at deep underground", Existing post-grouting methods for crystalline rock were reviewed, the applicability of pre-grouting technology was evaluated and study on experiment plan in MIU was carried out following the previous year.

Status of grouting to reduce groundwater inflow into deep shafts and galleries in the Mizunami Underground Research Laboratory, Japan

Sato, Toshinori; Mikake, Shinichiro; Kobayashi, Shinji*; Tsuji, Masakuni*

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

Japan Atomic Energy Agency is operating Mizunami Underground Research Laboratory project focusing on crystalline rock. Grouting for reducing water inflow is an essential countermeasure technology utilized during construction of underground facilities. Pre-excavation grouting and post-excavation grouting using Ordinary Portland cement, super-fine Portland cement and liquid-type colloidal silica were performed to investigate their performance as countermeasures for reducing groundwater inflow at many locations in the shafts and galleries in the laboratory. The results show that pre-excavation grouting successfully attained the target hydraulic conductivity of 2 Lu for Ordinary Portland cement and 0.2 Lu for super-fine Portland cement using criteria of Lugeon value and changing W/C. Liquid-type colloidal silica was able to drastically lower the hydraulic conductivity of 0.29 Lu and seemed to be stable for water pressures of at least 5 MPa and to be important material used in deep underground.

Study on engineering technologies in the Mizunami Underground Research Laboratory; FY2012 (Contract research)

Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Yoshinori*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.

JAEA-Technology 2014-019, 495 Pages, 2014/08

JAEA-Technology-2014-019.pdf:82.23MB

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

Simple determination of low power on reflected reactors using Feynman- experiment

Okajima, Shigeaki; Narita, M.*; Kobayashi, Keiji*

Annals of Nuclear Energy, 14(12), p.673 - 676, 1987/12

https://doi.org/10.1016/0306-4549(87)90005-3

When a low power meter for a reactor is calibrated by using the Feynman- methode, the absolute power is obtained by the product of the power deduced from the one-point reactor formula and the -factor which was introduced as the spatila correction factor on the Rossi- measurement. In this paper, for the purpose of ezperimental usage, formulae of the -factor for the different geometries are derived by one speed approximation and its characteristics are systematically surveyed. A simple formula of the -factor for a spherical core is presented and applied. This formula can estimate the value of the -factor with appropriate accuracy.

Grouting technology applied at 500 m depth of the Mizunami Underground Research laboratory, 1; Grouting design based on pre-boring investigation

Kobayashi, Shinji*; Tsuji, Masakuni*; Kusano, Takashi*; Ukai, Takaki*; Mikake, Shinichiro; Sato, Toshinori

no journal, , 

no abstracts in English

Comparison study of silica sol grouting at the TASS tunnel, Aspo Hard Rock Laboratory and Mizunami Underground Research Laboratory

Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro; Johan, F.*

no journal, , 

Silica sol is a material that seems to fulfill the non-hazardous requirement of final repository and capable of penetrating into narrow fractures. The rock grouting strategy with silica sol has been studied and applied for some recent projects in Sweden. The design methodology is based on the determination of the distribution of fracture transmissivity and the theoretical penetration length. In 2008, grouting with silica sol was applied in the construction of a short tunnel at 450 m depth in the Aspo Hard Rock Laboratory, the TASS-tunnel. In 2010, a grouting experiment with silica sol was performed at a niche of 300 m depth in the Mizunami Underground Research Laboratory, the MIU-300-niche. Despite the fact that silica sol has been used for a couple of decades for soil consolidation or sealing of fractures, it has seldom been applied as a material for rock grouting during tunneling.

Post-excavation grouting technology applied at 500 m depth of the Mizunami Underground Research Laboratory, 2; New design and water inflow prediction

Mikake, Shinichiro; Sato, Toshinori; Kobayashi, Shinji*; Tsuji, Masakuni*; Kurita, Kazuaki*; Eguchi, Keita*

no journal, , 

no abstracts in English