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JAEA Reports

Planning for in-situ backfilling test to the gallery in the Mizunami Underground Research Laboratory

Toguri, Satohito*; Yahagi, Ryoji*; Okihara, Mistunobu*; Takeuchi, Nobumitsu*; Kurosaki, Hiromi*; Matsui, Hiroya

JAEA-Technology 2018-017, 161 Pages, 2019/03

JAEA-Technology-2018-017.pdf:28.26MB

The Japan Atomic Energy Agency has been conducting research on three critical issues for development of: engineering techniques for underground construction, modelling techniques of mass transfer and tunnel backfilling methods at the Mizunami Underground Research Laboratory on the basis of Medium to Long-Term Plan of Japan Atomic Energy Agency. This report describes the overall plan of in-situ test to backfill a part of Mizunami Underground Research Laboratory, which is planned for "development of tunnel backfilling method".

Journal Articles

Application of data assimilation in groundwater hydrology; Characterization of hydraulic heterogeneity of hydrogeological structure based on in-situ data

Onoe, Hironori

Keisan Kogaku, 24(1), p.3851 - 3854, 2019/01

In this study, inverse analysis using observed data of pumping test was carried for confirmation of the applicability of inverse analysis method of groundwater flow based on in-situ data. Target of this inverse analysis was spatial distribution of hydrogeological heterogeneity of the fault. Inverse analysis had been applied to the area around the Mizunami Underground Research Laboratory, which is constructed by the Japan Atomic Energy Agency in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste. As a result of this study, the estimated results of inverse analysis are consistent with previous study result, and it was concluded that inverse analysis using hydraulic response due to pumping test is effective for hydrogeological characterization in deep underground.

JAEA Reports

Study on modeling and analysis of groundwater flow with inverse analysis, 2 (Joint research)

Onoe, Hironori; Yamamoto, Shinya*; Kohashi, Akio; Ozaki, Yusuke; Sakurai, Hideyuki*; Masumoto, Kiyoshi*

JAEA-Research 2018-003, 84 Pages, 2018/06

JAEA-Research-2018-003.pdf:17.44MB

In this study, numerical experiments considered hydrogeological structures, which has high heterogeneity around the Mizunami Underground Research Laboratory and inverse analysis using in-situ data were carried out. The results showed that concentration of hydrogeological structure to be estimated and location of monitoring point is important for application of inverse analysis. Furthermore, it is concluded that inverse analysis using hydraulic response due to pumping test is effective for hydrogeological characterization.

JAEA Reports

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.

Journal Articles

Mechanical characteristics of rock segment for reducing amount of cement use and stability of drift tunnel

Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Fujita, Tomoo; Sugita, Yutaka; Nakama, Shigeo; Sanada, Masanori*

Doboku Gakkai Rombunshu, F2 (Chika Kukan Kenkyu) (Internet), 73(1), p.11 - 28, 2017/03

This study examined the mechanical characteristics of rock segments and backfill materials and analyzed the stability of the drift that is supported by the rock segments and gravel backfill. The results confirmed the technical aspects of the formation of the rock segments and the effectiveness of the planned efforts to further reduce the amount of cement used.

Journal Articles

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$$^{-9}$$ m/s.

JAEA Reports

Study on modeling and analysis of groundwater flow with inverse analysis (Joint research)

Kohashi, Akio; Onoe, Hironori; Yamamoto, Shinya*; Honda, Makoto*; Sakurai, Hideyuki*; Masumoto, Kiyoshi*

JAEA-Research 2015-022, 89 Pages, 2016/03

JAEA-Research-2015-022.pdf:27.85MB

In Japan, high-level radioactive waste (HLW) will be emplaced in a stable host rock formation deeper than 300 meters underground for geological disposal. It is important to understand heterogeneous distribution of hydraulic conductivity from the viewpoints of the safety assessment of geological disposal of HLW and construction of underground facilities. Inverse analysis based on the transient data is an efficient technique for estimating the heterogeneous distribution. In this study, numerical experiments with the adjoint state method and the ensemble Kalman filter were carried out in order to understand effective method for application of these inverse analysis. As a result of this study, the capability of each analysis techniques was shown.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2014); Development of design and construction planning and countermeasure technologies (Contract research)

Kobayashi, Shinji*; Niimi, Katsuyuki*; Tsuji, Masakuni*; Yamada, Toshiko*; Aoyagi, Yoshiaki; Sato, Toshinori; Mikake, Shinichiro; Osawa, Hideaki

JAEA-Technology 2015-039, 170 Pages, 2016/02

JAEA-Technology-2015-039.pdf:37.73MB

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. For the characteristics of earthquake ground motion, measurement data obtained by seismometers installed in the Mizunami Underground Laboratory were analyzed, and the comprehensive assessment of the relationship between the measurement data and the geological condition at each depth was performed. As for "Study on grouting method at deep underground ", post grouting was carried out and evaluated based on the Construction plan in FY2013. Furthermore, target of the future R&D was proposed.

JAEA Reports

Influence of fuel assembly loading pattern and fuel burnups upon leakage neutron flux spectra from light water reactor core (Joint research)

Kojima, Kensuke; Okumura, Keisuke; Kosako, Kazuaki*; Torii, Kazutaka*

JAEA-Research 2015-019, 90 Pages, 2016/01

JAEA-Research-2015-019.pdf:1.95MB

At the decommissioning of light water reactors (LWRs), it is important to evaluate an amount of radioactivity in the ex-core structures such as a reactor containment vessel, radiation shieldings, and so on. It is thought that the leakage neutron spectra in these radioactivation regions, which strongly affect the induced radioactivity, would be changed by different reactor core configurations such as fuel assembly loading pattern and fuel burnups. This study was intended to evaluate these effects. For the purpose, firstly, partial neutron currents on the core surfaces were calculated for some core configurations. Then, the leakage neutron flux spectra in major radioactivation regions were calculated based on the provided currents. Finally, influence of the core configurations upon the neutron flux spectra was evaluated. As a result, it has been found that the influence is small on the spectrum shapes of neutron fluxes. However, it is necessary to pay attention to the facts that intensities of the leakage neutron fluxes are changed by the configurations and that intensities and spectrum shapes of the leakage neutron fluxes are changed depending on the angular direction around the core.

Journal Articles

Grouting for reducing groundwater inflow into a gallery at 500m depth of the Mizunami Underground Research Laboratory, Japan

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

Proceedings of the ISRM Regional Symposium EUROCK 2015 & 64th Geomechanics Colloquium; Future Development of Rock Mechanics, p.35 - 41, 2015/10

Rock grouting has been an essential measure to reduce water ingress into the deep underground during the excavation of Mizunami Underground Research Laboratory project in Japan. This paper shows an overview of grouting works performed at a gallery of 120 m at 500 m depth. After completion of its excavation with the pilot borehole investigation and pre-grouting mainly by Super-fine Portland cement, the inflow from the whole gallery was 200-220 Liter/min within the requirement. Then, at a limited section of 16 m, post-grouting was performed with new designs, applying colloidal silica grout, complex dynamic grouting, and grouting outside of the pregrouted zone. These designs were effective and the inflow at the section reduced from 35 to 11 Liter/min. These experiences must be fruitful for advancing the present technology and there should have been potential for reducing further inflow if any of the new designs are applied from the pre-grouting phase.

Journal Articles

Excavation cycle times recorded during sinking of a deep shaft in crystalline rock; A Case example at ventilation shaft of Mizunami URL, Japan

Sanada, Hiroyuki; Sato, Toshinori; Horiuchi, Yasuharu*; Mikake, Shinichiro; Okihara, Mistunobu*; Yahagi, Ryoji*; Kobayashi, Shinji*

Tunnelling and Underground Space Technology, 50, p.68 - 78, 2015/08

 Times Cited Count:3 Percentile:75.02(Construction & Building Technology)

The Japan Atomic Energy Agency (JAEA) is implementing the Mizunami Underground Research Laboratory (MIU) Project to establish the scientific and technological basis for the geological disposal of High-level Radioactive Waste (HLW) in crystalline rocks. Excavation cycle times were recorded during the Ventilation Shaft sinking and compared with the planned excavation cycle times for evaluation of the baseline design plan. This included review of the cycle times in the design process and comparison with the actual construction results. The recorded results indicate that actual cycle times were twice as long as the design plan. This paper describes discussions on differences in cycle times between the design and actual times.

JAEA Reports

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, Mistunobu*; 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.

Journal Articles

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

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

Dai-43-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.7 - 12, 2015/01

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 an developed as there is less experience of grouting in low conductive rock with high water pressure, especially in Japan. Ahead of excavating GL.-500m gallery on the ventilation shaft side, grouting design was performed based on the estimation of water inflow by the pilot-boring investigations and the design was properly revised during the campaign. The gallery satisfied the inflow requirement with good sealing effect.

Journal Articles

Analysis of excavation cycle time during sinking of the ventilation shaft at the Mizunami Underground Research Laboratory

Sanada, Hiroyuki; Sato, Toshinori; Horiuchi, Yasuharu*; Mikake, Shinichiro; Okihara, Mistunobu*; Yahagi, Ryoji*; Kobayashi, Shinji*

Proceedings of 8th Asian Rock Mechanics Symposium (ARMS-8) (USB Flash Drive), 7 Pages, 2014/10

The Japan Atomic Energy Agency (JAEA) is implementing the Mizunami Underground Research Laboratory (MIU) Project to establish the scientific and technological basis for the geological disposal of High-level Radioactive Waste (HLW) in crystalline rocks. Excavation cycle times were recorded during the Ventilation Shaft sinking and compared with the planned excavation cycle times for evaluation of the baseline design plan. This included review of the cycle times in the design process and comparison with the actual construction results. The recorded results indicate that actual cycle times were twice as long as the design plan. This paper describes discussions on differences in cycle times between the design and result.

Journal Articles

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.

Journal Articles

Comparison of grouting with silica sol in the $"A$sp$"o$ Hard Rock Laboratory in Sweden and Mizunami Underground Research Laboratory in Japan

Tsuji, Masakuni*; Funehag, J.*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro

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

Silica sol is a material that seems to fulfill the non-hazardous requirement 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 fracture transmissivity distribution 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 $"A$sp$"o$ Hard Rock Laboratory, the TASS-tunnel. In 2010, a grouting experiment with silica sol was performed in a gallery at 300 m depth in the Mizunami Underground Research Laboratory (MIU experiment). It can be suggested that Swedish methodology can be applied to design and evaluate the grouting works in Japanese rock with higher intensity of fractures in general. Furthermore, an additional pumping time or the use of Japanese silica sol might improve the grouting quality in Sweden.

JAEA Reports

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.

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.

Journal Articles

Development of rock segment for reduction of amount of cement use

Tada, Hiroyuki*; Kumasaka, Hiroo*; Saito, Akira*; Nakaya, Atsushi*; Ishii, Takashi*; Sanada, Masanori; Noguchi, Akira*; Kishi, Hirokazu*; Nakama, Shigeo; Fujita, Tomoo

Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.133 - 138, 2013/01

The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkaline mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of tunnel supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the alternative supports planned for further reduction in cement influence was confirmed from a study result above-mentioned.

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.

116 (Records 1-20 displayed on this page)