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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, Tomo

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.

Journal Articles

Development of grouting technologies for geological disposal of high level waste in Japan, 2; Selection of grout materials

Kawaguchi, Masanao; Kishi, Hirokazu*; Fujita, Tomo; Kishida, Kiyoshi*

Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.337 - 342, 2013/01

For the selection of grout material for the construction of underground facilities for the geological disposal of High Level Waste, the criteria that is set by reference to IMA-project(which was a project of the grout material relating to the R20 program was conducted by POSIVA of Finland), has been used up to FY 2010. However, if the criteria of penetrability are fulfilled, the penetrability of the material for the candidate rock fracture is not ensured. Moreover, from the results of laboratory grout penetration test which has been carried out at FY 2010, it was appeared that the penetrability has been scarified in order to satisfy the strength and breeding characteristics. In this report, strength and bleeding properties are classified as reference properties, not as principal properties. Instead of that, new criteria of penetrability defined based on geological features at the site are proposed. Also the determination procedure of designed hydraulic fracture aperture which is one of above newly proposed criteria will be proposed.

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

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

Tsuda, Hidenori; Walker, C.; Shinkai, Fumiaki*; Kishi, Hirokazu*; Yui, Mikazu

Journal of Nuclear Science and Technology, 49(11), p.1110 - 1113, 2012/11

 Times Cited Count:4 Percentile:36.4(Nuclear Science & Technology)

JAEA Reports

Studies about strength recovery and generalized relaxation behavior of rock, 5

Sanada, Masanori; Kishi, Hirokazu*; Sugita, Yutaka; Hayashi, Katsuhiko*; Takebe, Atsuji*; Okubo, Seisuke*

JAEA-Research 2012-025, 130 Pages, 2012/09

JAEA-Research-2012-025.pdf:4.12MB

In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, by using the value of a suitable constant with the constitutive equation showing strength recovery, it was showed that change of the axial stress in a compacting test could be expressed. About the generalized relaxation, it examined by the air dried and the saturated condition. Visco-elastic behavior was more remarkable in saturated condition than the air dried. Moreover, when the loading rate up to the starting point of the generalized relaxation test was large, the influence on visco-elastic behavior was remarkable. About tensile characteristics, a splitting tensile strength test and a uniaxial tensile strength test were carried out. About splitting tensile strength, it turned out that the influence of the loading direction on a bedding plane is great.

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

The JAEA grouting test at the Grimsel test site; Numerical simulation of the grout injection process of silica sol in fractured rock mass

Koyama, Tomofumi*; Onishi, Yuzo*; Bruines, P.*; Tanaka, Tatsuya*; Hasui, Akinori*; Katayama, Tatsuo*; Kishi, Hirokazu; Kuzuha, Yuji

Proceedings of 2012 ISRM International Symposium; Rock Engineering and Technology for Sustainable Underground Construction (EUROCK 2012) (USB Flash Drive), 10 Pages, 2012/05

Grouting, which involves injection of grout material, is commonly used to decrease the hydraulic conductivity of the fractured rock masses and control the groundwater inflow. However, the mechanism of grout injection process has not been clarified sufficiently yet due to complicated chemical and physical processes of grout. In this study, to simulate the grout injection process, the three-dimensional numerical model based on equivalent continuum approach was developed.

Journal Articles

The JAEA grouting test at the Grimsel test site; Site characterization of a fractured rockmass and preparation of DFN model and its equivalent continuous porous media model

Bruines, P.*; Tanaka, Tatsuya*; Koyama, Tomofumi*; Kishi, Hirokazu; Nakanishi, Tatsuro; Onishi, Yuzo*

Proceedings of 2012 ISRM International Symposium; Rock Engineering and Technology for Sustainable Underground Construction (EUROCK 2012) (USB Flash Drive), 15 Pages, 2012/05

To better understand the grouting process and the effect of grouting on the performance of a nuclear waste repository, the Japanese Atomic Energy Agency (JAEA) has initiated a grouting test carried out in the fractured granite of the Grimsel Test Site (GTS) located in the Swiss Alps. This paper describes the characterization of the rock mass, how the data obtained has been used to make a discrete fracture network (DFN) model and how an up-scaled equivalent continuous porous media (ECPM) model for the purpose of numerical simulation of the grout injection process is generated. The generated DFN model and the up-scaled ECPM model was able to reproduce the measured fracture characteristics (e.g. orientation, density) as well as the hydraulic behavior observed in the field (e.g. transmissivity distribution, anisotropy, heterogeneity) and has proven to be suitable for modeling grouting behavior.

JAEA Reports

Studies on the design method of multi tunnels in geological disposal facility, 5

Sanada, Masanori; Kishi, Hirokazu; Hayashi, Katsuhiko*; Takebe, Atsuji*

JAEA-Research 2011-055, 79 Pages, 2012/03

JAEA-Research-2011-055.pdf:4.11MB

In order to refine and rationalize a design method of multi tunnels in the deep geological repository, various study have been conducted. In this study, an effect of procedure for excavating multi-tunnels on extent of EDZ was examined by 3D FEM analysis. In modeling the multi tunnels and setting cases of analysis, workability, cost and safeness under construction were considered. Results of 3D FEM analysis showed that 3D effect of procedure for excavating such as a gap of progress with tunnel faces can be considered by 3D FEM and extent of EDZ is demonstrated more practically compared with 2D FEM. Another 2D FEM analysis modeling for crystalline rock (granite) was executed and the results showed that plastic zone did not appear in all cases.

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

Development of grouting technologies for geological disposal of high level waste in Japan, 3; Numerical simulation for grout injection using equivalent continuum model

Koyama, Tomofumi*; Katayama, Tatsuo*; Hasui, Akinori*; Tanaka, Tatsuya*; Kishi, Hirokazu; Onishi, Yuzo*

Dai-41-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.83 - 88, 2012/01

In this study, to simulate the grout injection process, the 3-D numerical model based on equivalent continuum approach was developed. The viscosity measurements for silica sol was performed to measure the time-dependent viscosity. The developed numerical model was applied to the planned in-situ grout injection tests at Grimsel test site (GTS), Switzerland. The rock type is fractured granite and the equivalent porous media was created from the DFN (Discrete Fracture Network) based on the frature data obtained from the observation boreholes. The preliminary simulation was carried out to determine the suitable grout injection pressure and investigate the arrival distance of grout from injection boreholes.

JAEA Reports

Studies about strength recovery and generalized relaxation behavior of rock, 4

Sanada, Masanori; Hayashi, Katsuhiko*; Kishi, Hirokazu; Takebe, Atsuji*; Okubo, Seisuke*

JAEA-Research 2011-028, 102 Pages, 2011/11

JAEA-Research-2011-028.pdf:3.08MB

In this study, strength recovery, generalized stress relaxation and two tensile strength tests were carried out using shale sampled in the Wakkanai-formation. As the results, recovery of failed rocks in strength and hydraulic conductivity were observed under a certain condition. We believe this result is very important for the stability evaluation of underground space in the bedrock that needs good sealing up characteristic, isolation characteristic, safety and high reliability for long term. Generalized stress relaxation test was conducted submerging samples in water. Experimental results showed comparatively smaller scatter than those in air-dried condition. It was also found that testing results were affected by strain rate up to the starting point of generalized relaxation test. Indirect and uniaxial tensile strength tests were also conducted submerging samples in water and smaller tensile strength with smaller scatter were obtained than those in air-dried condition.

Journal Articles

Mix design of low pH cement shotcrete in high level radioactive waste repositories

Noguchi, Akira; Kishi, Hirokazu; Hatanaka, Koichiro; Naito, Morimasa

Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 6 Pages, 2011/10

A standardized method for choosing a mix design of low pH shotcrete is proposed for their intended use in the construction of a High Level Radioactive Waste (HLW) repository in order to be applied to the various geological environment of the location of the HLW repositories. There are two improvement in this method. One is estimating binder composition to satisfy low pH. The other is estimating water bender ratio to satisfy the strength of sprayed concrete. The method uses a sequential development process with consideration given to a number of physicochemical requirements, incorporates current shotcrete technology. The method is demonstrated in its entirety through a series of experiments and tests using a low pH cement binder comprised of a mixture of ordinary Portland cement, fly ash (FA) and silica fume (SF), referred to here as high-volume FA SF cement (HFSC). Moreover, the method is referred from the demonstration of HFSC shotcrete in Horonobe underground research laboratory.

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

The Project for grouting development for high level radioactive waste repository, 8; Prediction analysis of grout injection in equivalent porous media

Kuzuha, Yuji; Kishi, Hirokazu; Hasui, Akinori*; Katayama, Tatsuo*; Koyama, Tomofumi*

Doboku Gakkai Heisei-23-Nendo Zenkoku Taikai Dai-66-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.79 - 80, 2011/09

no abstracts in English

JAEA Reports

Studies on the design method of multi tunnels in geological disposal facility, 4

Hayashi, Katsuhiko; Kishi, Hirokazu; Kabayashi, Yasushi*; Takebe, Atsuji*; Fujiyama, Tetsuo*; Hiramoto, Masayuki*; Mizutani, Kazuhiko*; Morita, Atsushi*

JAEA-Research 2010-059, 92 Pages, 2011/03

JAEA-Research-2010-059.pdf:3.71MB

In this study, the first investigation is the order of the multi-tunnels excavation. The second is the strain-softening model for multi-tunnels which is based on test data at Horonobe site. As results of first investigation, we showed as 2 dimensional analyses that it was desirable to excavate the tunnel of the remote distance at first and excavate the tunnel between these tunnels next, and it is necessary for the examination that reflected a real plan, such as evacuation machine and actual multi tunnel layout. As the results of second investigation, we also showed the more reliable EDZ by using the strain-softening model that is based on test data at Horonobe site. Furthermore, we standardized the design method (draft) for the practical use by referring the past studies of multi tunnel design method.

JAEA Reports

A Study on the technology for reducing cement-type materials used for tunnel supports at high-level radioactive waste disposal sites (Joint research)

Hayashi, Katsuhiko; Noguchi, Akira; Kishi, Hirokazu; Kabayashi, Yasushi*; Nakama, Shigeo; Fujita, Tomo; Naito, Morimasa; Tada, Hiroyuki*; Kumasaka, Hiroo*; Goke, Mitsuo*; et al.

JAEA-Research 2010-057, 101 Pages, 2011/03

JAEA-Research-2010-057.pdf:7.47MB

Cement-type materials that are used for supports or grouting at high-level radioactive waste disposal facilities leach into the groundwater and create a highly alkaline environment. Of concern in highly alkaline environments are the alteration of bentonite used as buffers or backfill materials, and of surrounding rock mass, and the increased uncertainty regarding the provision of performance of the disposal system over a long period of time. In this study, to reduce the quantity of cement-type materials that cause highly alkaline environments, technical feasibility of the support structure including the materials which considered the long-term performance of the HLW disposal system are discussed by using knowledge and technology accumulated in JAEA and Shimizu Construction. Moreover, based on the results, the problems remained in the application to the future HLW disposal institution are summarized.

Journal Articles

The Project for grouting development for high level radioactive waste repository, 4; Development of superfine spherical silica grout

Yamada, Tsutomu*; Sekine, Ichiro*; Sekiguchi, Takashi*; Ishida, Hideaki*; Kishi, Hirokazu; Fukuoka, Naomi

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.89 - 90, 2010/09

no abstracts in English

Journal Articles

The Project for grouting development for high level radioactive waste repository, 5; In-situ grouting experiment at the Horonobe URL

Kishi, Hirokazu; Izumi, Atsushi; Toida, Masaru*

Doboku Gakkai Heisei-22-Nendo Zenkoku Taikai Dai-65-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.91 - 92, 2010/09

no abstracts in English

31 (Records 1-20 displayed on this page)