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Journal Articles

Transition of near surface resistivity of tunnel wall during drift closure test

Ozaki, Yusuke; Ishibashi, Masayuki; Matsushita, Tomoaki*; Masumoto, Kazuhiko*; Imasato, Takehiko*

Proceedings of 13th SEGJ International Symposium (USB Flash Drive), 4 Pages, 2018/11

In the Mizunami Underground Research Laboratory, Groundwater REcoverty Experiment in Tunnel (GREET) is performed to understanding the recovery process of geological environment after the closure of drift. In this experiment, we performed 2D electrical resistivity surveys three times. First survey was performed before the closure of test drift. Second and third surveys were performed after the closure test. The first survey detected two layers conformation that consists of conductive and resistive zones at shallower and deeper part from the drift surface, respectively. These layers correspond to the shotcrete and host rock, respectively. Second and third measurements show that the conductive zone expanded to deeper resistive part while the shallower conductive part did not change. We concluded that we captured the saturation process of dried fractures near the drift wall by closure of drift as an electrical resistivity response.

Journal Articles

Evaluation of fractures in a rock as flow paths around tunnel using ground penetrating radar

Masumoto, Kazuhiko*; Takeuchi, Ryuji

Oyo Chishitsu, 57(4), p.154 - 161, 2016/10

Fractures developing around the tunnel during the excavation result in issues related not only to the mechanical stability of the rock cavern, but also to the groundwater flow paths. In order to estimate the possibility of application of the GPR (Ground Penetration Radar) to estimate the fractures as low paths, the authors conducted the GPR survey along the side wall of 500 m access tunnel of the Mizunami Underground Research Laboratory of JAEA. The results of the profile measurements indicated that water-conductiong fractures were detected as a reflected waves using GPR survay. Furthermore, as the results of fixed-point measurements during the injection of the saline water, it could be indicated to estimate the flow paths of saline water in the fractures, in a non-destructive way, based on spectral analysis in the reflected waveforms of GPR.

Journal Articles

Discrete fracture network modeling based on in-situ data at underground gallery, 1

Ishibashi, Masayuki; Onoe, Hironori; Sawada, Atsushi; Atsumi, Hiroyuki*; Masumoto, Kazuhiko*; Hosoya, Shinichi*

Dai-42-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.101 - 106, 2014/01

Japan Atomic Energy Agency is proceeding with the Mizunami Underground Research Laboratory Project in order to establish comprehensive techniques for the investigation, analysis and assessment of the deep geological environment in fractured crystalline rock for geological disposal of high level radioactive wastes. We have carried out discrete fracture network modeling, groundwater flow and particle tracking simulation in order to understand the important factors for the solute transport characterizations. In this paper, a method of discrete fracture network modeling based on in-situ data at underground gallery and the influences of different data interpretation are described.

Journal Articles

Full-scale experimental study on mechanical behavior of a clay plug under HLW disposal conditions

Sasakura, Takeshi*; Masumoto, Kazuhiko*; Toida, Masaru*; Fujita, Tomoo; Sugita, Yutaka

Proceedings of 9th International Conference on Geo-environmental Engineering (GEE 2010), p.47 - 56, 2010/05

High level radioactive waste is to be vitrified, and after some period of storage for cooling, put into engineered barriers such as metal canister, overpack and buffer material, and finally disposed of in the stable geology at the depth of 300 m or deeper to isolate from human environment for a long period of time in Japan. The geological repository consists of surface facilities and subsurface facilities; the later, mainly consists of tunnels for transportation and waste emplacement, will be closed using sealing technologies such as backfilling, plugging, and grouting after emplacement of the waste to prevent seepage of radionuclides for a long period of time. Effectiveness of these sealing technologies, however, has not been well demonstrated in-situ worldwide, and the technologies may be considered in the stage of research and development. Therefore, in this paper, the in-situ tunnel sealing test performed at Canada to demonstrate the effectiveness of the plug under crystalline rock environment was overviewed focusing on the plug. Then behavior of the plug, particular of mechanical behavior, during sealing tests, observation result of dismantled plug were reviewed and points to be addressed for establishing the clay plug technology were identified. Because the procedure of this tunnel sealing test and hydraulic sealing performance of the plug has already been precisely reported by Fujita et al. (2007), outline of the test is briefly summarized and mechanical behavior of the plug was focused. As a result, effectiveness of conventional construction technology of a plug was shown, the behavior of a plug during the pressurization test was clarified and important points to be addressed for establishing the clay plug technology were identified.

JAEA Reports

Assessment of heterogeneous geological environment at Tono -Japanese fiscal year 2004- (Contract research)

Toida, Masaru*; Suyama, Yasuhiro*; Mori, Takayuki*; Inaba, Takeshi*; Sasakura, Takeshi*; Atsumi, Hiroyuki*; Masumoto, Kazuhiko*; Kobayashi, Ichizo*; Iwano, Keita*; Furuichi, Mitsuaki*; et al.

JAEA-Research 2007-065, 210 Pages, 2007/09

JAEA-Research-2007-065-1.pdf:28.82MB
JAEA-Research-2007-065-2.pdf:42.37MB
JAEA-Research-2007-065-3.pdf:24.46MB
JAEA-Research-2007-065-4.pdf:48.78MB

"Geoscientific research" at the Tono Area is developing site investigation, characterization and assessment techniques for understanding of geological environment. Their important goals are to establish a methodology for analyzing uncertainties in heterogeneous geological environment and to develop investigation techniques for efficiently reducing the uncertainties. The current study proposes a new approach where all the possible options in the models and data-sets, which cannot be excluded in the light of the evidences available, are identified. This approach enables uncertainties associated with the understanding at a given stage of the site characterization to be made explicitly using an uncertainty analysis technique based on Fuzzy geostatistics. This approach supports the design of the following investigation stage and reduces the uncertainties efficiently. In FY H16 the technique has been tested through geological modelling and groundwater analyses with Tono Area case based on current knowledge, to demonstrate its applicability and to compile the knowledge / information required to describe the H17 report. This report can be summarized as follows: (1) The knowledge / information required to describe the heterogeneous characteristics was compiled and connected to uncertainties associated with the characterization of a geological environment using a synthesis diagram. (2) Methodologies for assignment and screening of parameters were developed by using Evidential Support Logic (ESL). (3) Applicability of the techniques could be confirmed with Tono Area case. (4) This report proposed a new methodology that integrates the technique into JAEA ordinary technique to good advantage in the geoscientific research project.

Journal Articles

Investigation of the EDZ using high-resolution GPR with modulating frequency

Suyama, Yasuhiro*; Toida, Masaru*; Masumoto, Kazuhiko*; Takeuchi, Shinji

Proceedings of 12th European Meeting of Environmental and Engineering Geophysics (Near Surface 2006) (CD-ROM), 5 Pages, 2006/09

The EDZ is considered to be a fast transport pathway and provides a boundary condition for transport in bentonite buffers in groundwater scenarios for the geological disposal of radioactive waste. The distribution of the EDZ obtained through in-situ measurements, is important for safety assessments. High-resolution Ground Penetrating Radar (HGPR) with modulating frequency functions as a wide-angle measurement technique. It is one of the advanced techniques that can be used to investigate the EDZ of a radioactive waste disposal tunnel. Verification tests of the HGPR were carried out using a model and in-situ, in the gallery of Tono mine in central Japan. In summary, it is shown that the investigation technique was able to detect underground structures with a resolution of less than 0.1m.

Journal Articles

The Tunnel Sealing Experiment: A Review

Fujita, Tomoo; Martino, J. B.*; Dixon, D. A.*; Kozak, E. T.*; Vignal, B.*; Sugita, Yutaka; Masumoto, Kazuhiko*

CD-ROM, 12p., 12 Pages, 2005/05

The Tunnel Sealing Experiment (TSX), a major international experiment, demonstrating technologies for tunnel sealing at full-scale, was conducted at Atomic Energy of Canada Limited's Underground Research Laboratory (URL). The objective of the experiment was to demonstrate technologies for construction of bentonite and concrete bulkheads, to quantify the performance of each bulkhead and to document the factors that affect the performance. It was not the purpose of the experiment to demonstrate an optimized bulkhead. Two bulkheads, one composed of low heat high performance concrete and the other of highly compacted sand-bentonite material, were constructed in a tunnel in unfractured granitic rock at the URL. The chamber between the two bulkheads was pressurized to 4 MPa in a series of steps over a two-year period. The ultimate pressure is representative of the ambient pore pressures in the rock at a depth of 420 m. The first phase of the TSX was at ambient temperature (15$$^{circ}$$C), and the second phase ultimately reached 65$$^{circ}$$C at thermistors near the upstream face of the bulkheads. Instrumentation in the experiment monitored parameters that are important indicators for bulkhead performance. Seepage was measured at both bulkheads and any leakage points from the tunnel to maintain a water balance. The paper provides an overview of the project.

JAEA Reports

Study for Evaluation of Performance of Sealing Technique

Toida, Masaru*; Sasakura, Takeshi*; Atsumi, Hiroyuki*; Masumoto, Kazuhiko*; Tanaka, Toshiyuki*; Suyama, Yasuhiro*; Kobayashi, Ichizo*

JNC TJ8400 2004-023, 146 Pages, 2005/02

JNC-TJ8400-2004-023.pdf:11.18MB

To establish sealing technique suitable for geological environmental conditions of Japan, it is necessary to obtain data related with this sealing function through laboratory tests and in-situ tests. It also is necessary to put these data to practical use and to establish the estimating method of the sealing technique.Tunnel sealing experiment, which has been carried out as collaboration between JNC and AECL at URL of AECL Canada, is progressing in the final stage and fundamental data relating with the sealing function has almost obtained. This report deals with the total data processing and interpretation of the sealing experiment, as well as the numerical analysis and interpretation on tracer test results. Conceptual plans of the experiment to confirm the performance of tunnel sealing technique in a sedimentary rock are also discussed.

JAEA Reports

Mizunami Underground Research Project, Annual report in the 2002 fiscal year

Ota, Kunio; Amano, Kenji; Kumazaki, Naoki; Matsuoka, Toshiyuki; Takeuchi, Shinji; Masumoto, Kazuhiko; Yabuuchi, Satoshi

JNC TN7410 2003-006, 127 Pages, 2003/07

JNC-TN7410-2003-006.pdf:7.94MB
JNC-TN7410-2003-006(errata).pdf:0.08MB

The current geoscientific research of the Mizunami Underground Research Laboratory (MIU) Project have been carried out since the 1996 fiscal year at the Shobasama site in Akeyo-cho, Mizunami City, Gifu Prefecture. The main goals of the MIU Project are to establish appropriate methodologies for reliably investigating and assessing the deep subsurface, and to develop a range of engineering techniques for deep underground application in granite. The site for MIU construction was changed in January 2002, from the Shobasama site to city-owned land (MIU Construction Site) after lease contract with Mizunami city. The surface-based investigations at the MIU facility site have started since February 2002. In 2002 fiscal year, geophysical survey and shallow borehole investigations was conducted and deep borehole investigations have started for modeling and characterization of geological environment in the MIU Construction Site before sinking the shafts. Detail of study and survey during the construction phase of MIU project was planned based on the layout and plan of construction of the underground facilities for development of engineering technologies in a deep underground. In Shobasama site, VSP survey was carried out to improve the model of geological environment. Hydrogeological model was calibrated using the results of long-term pumping test and long-term subsurface and groundwater monitoring. Important factors for hydrogeological modeling were evaluated as the results of numerical analysis by multiple approaches of groundwater flow modeling. The preliminary analysis based on the rock mechanical model at the Shobasama site was performed to estimate the deformation caused by excavation of the underground facilities.

JAEA Reports

Design and construction technology of the engineered scale plug in the TSX

Sugita, Yutaka; Masumoto, Kazuhiko*

JNC TN8400 2002-005, 54 Pages, 2002/02

JNC-TN8400-2002-005.pdf:15.55MB

JNC has conducted the international joint project "Tunnel Sealing Experiment (TSX)" with AECL at Underground Research Laboratory-(URL) in Canada. Full-scale sealing technologies are applied to the underground tunnel in the TSX. Sealing technologies contain backfilling, plugging, grouting and so on. Since development of the plugging technology has impact to the whole sealing technology, understanding of the sealing performance of the plug is one of the most important problems. The TSX has full-scale concrete plug and clay plug. The sealing performance of the plugs has been monitored with the various sensors in and around the plugs, and assessed by the monitored data. This report summaries the design and construction technology of the plugs in the TSX. The design of the plugs focused on the impervious (seepage control). The concrete plug selected the shape and the size of the body and the size of the key considering the attachment between plug and rock mass. The clay plug selected the shape and the size of the key considering the volume of the EDZ. The material of the concrete plug was Low-Heat High-Performance Concrete. The material of the clay plug was pre-compacted bentonite blocks with sand. Feasibility of design and construction of both plugs were demonstrated with engineer scale and in-situ full-scale plugs.

JAEA Reports

Full-scale demonstration of sealing technique in geological disposal, 2

Toida, Masaru*; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Suyama, Yasuhiro*; Abe, Yasunori*; Furuichi, Mitsuaki*; *

JNC TJ8400 2002-018, 159 Pages, 2002/02

JNC-TJ8400-2002-018.pdf:1.77MB

For the geological disposal of high level radioactive wastes, after placement of the wastes, it is necessary to close off (to be called "sealing" hereafter) the underground potential passages (disposal pits, disposal tunnels, main and connecting tunnels and access tunnels) with an effective combination of engineered barriers such as buffers, backfilling materials, plugs and grout. It is necessary to ensure the long-term durability to isolate disposed wastes in the system. The results of the research works this year are as follows ; (1) Basic data could be measured in the tunnel sealing experiments at URL site for sealing performance as the result of seepage, swelling pressure, evaporation rate and tracer concentration in and around the plug with increase of chamber pressure. (2) The transport properties around the plug could be evaluated based on a comparison between the results of tracer test and numerical analysis. (3) The sealing concept of foreign countries could be reviewed to establish the Japanese sealing concept and to clarify the requirement for sealing technique. This work was performed by KAJIMA Corporation under contract with Japan Nuclear Cycle Development Agency.

JAEA Reports

Full-scale demonstration of Sealing Technique in Geological Disposal, 2

Toida, Masaru*; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Suyama, Yasuhiro*; Abe, Yasunori*; Furuichi, Mitsuaki*

JNC TJ8400 2002-017, 159 Pages, 2002/02

JNC-TJ8400-2002-017.pdf:60.88MB

For the geological disposal of high level radioactive wastes, after placement of the wastes, it is necessary to close off (to be called "sealing" hereafter) the underground potential passages (disposal pits, disposal tunnels, main and connecting tunnels and access tunnels) with an effective combination of engineered barriers such as buffers, backfilling materials, plugs and grout. It is necessary to ensure the long-term durability to isolate disposed wastes in the system. The results of the research works this year are as follows ; (1) Basic data could be measured in the tunnel sealing experiments at URL site for sealing performance as the result of seepage, swelling pressure, evaporation rate and tracer concentration in and around the plug with increase of chamber pressure. (2) The transport properties around the plug could be evaluated based on a comparison between the results of tracer test and numerical analysis. (3) The sealing concept of foreign countries could be reviewed to establish the Japanese sealing concept and to clarify the requirement for sealing technique.

JAEA Reports

None

Toida, Masaru*; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Suyama, Yasuhiro; Abe, Yasunori*; Furuichi, Mitsuaki*

JNC TJ7440 2001-015, 103 Pages, 2001/03

JNC-TJ7440-2001-015.pdf:3.74MB

no abstracts in English

JAEA Reports

Full-scale demonstration of sealing technique in geological disposal

Toida, Masaru*; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Suyama, Yasuhiro*; Abe, Yasunori*; Furuichi, Mitsuaki*

JNC TJ8400 2001-019, 68 Pages, 2001/02

JNC-TJ8400-2001-019.pdf:9.26MB

no abstracts in English

JAEA Reports

Full-scale demonstration of sealing technique in geological disposal

Toida, Masaru*; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Suyama, Yasuhiro*; Abe, Yasunori*; Furuichi, Mitsuaki*

JNC TJ8400 2001-018, 212 Pages, 2001/02

JNC-TJ8400-2001-018.pdf:35.39MB

For the geological disposal of high level radioactive wastes, after placement of the wastes, it is necessary to close off (to be called sealing hereafter) the udergroud potential passages (disposal pits, disposal tunnels, main and connectimg tunnels and access tunnels) with an effective combination of engineered barriers such as buffers, backfilling materials, plugs alld grout. It is necessary to ensure the long-term durability to isolate disposed wastes in the system. The results of the research works this year are as follows; (1)It could be estimated in the tunnel sealing experiments at URL site that seepage, swelling pressure and tracer concentration in the plug were changed with increase of pressure. (2)The transport properties around the plug could be evaluated based on a comparison between the results of tracer test and numerical analysis.

JAEA Reports

Investigation on sealing technique in geological disposal

Furuichi, Mitsuaki*; Toida, Masaru*; Masumoto, Kazuhiko*

JNC TJ8400 2000-021, 196 Pages, 2000/02

JNC-TJ8400-2000-021.pdf:23.23MB

For the geological disposal of high level radioactive wastes, after placement of tbe wastes, it is necessary to close off (to be called "sealing" hereafter) the underground potential passages (disposal pits, disposal tunnels, main and connecting tunnels and access tunnels) with an effective combination of engineered barriers such as buffers, backfilling materials, plugs and grout. It is necessary to ensure the long-term durability to isolate disposed wastes in the system. The results of the research works this year are as follows; (1)The objectives are to discuss the design of tunnel sealing experiments at URL site. The results of research were about (a)tracer experiment and numerical analysis (b)evaporation measurement (c)presentation at the coordination meeting (2)The discussion was about the equipment of inclined compaction methods and bearing capacity of rock against pressures for the concrete plugs.

JAEA Reports

Investigation on sealing technique in geological disposal

Toida, Masaru*; Masumoto, Kazuhiko*; *; Okutsu, Kazuo*; *

JNC TJ8400 2000-020, 68 Pages, 2000/02

JNC-TJ8400-2000-020.pdf:9.45MB

For the geological disposal of high level radioactive wastes, after placement of the wastes, it is necessary to close off (to be called "sealing" hereafter) the underground potential passages (disposal pits, disposal tunnels, main and connecting tunnels and access tunnels) with an effective combination of engineered barriers such as buffers, backfiling materials, plugs and grout. It is necessary to ensure the long-term durability to isolate disposed wastes in the system. The results of the research works this year are as follows ; (1)The objectives are to discuss the design of tunnel sealing experiments at URL site. The results of research were about (a)tracer experiment and numerical analysis (b)evaporation measurement (c)presentation at the coordination meeting. (2)The discussion was about the equipment of inclined compaction methods and bearing capacity of rock against pressures for the concrete plugs.

JAEA Reports

None

Toida, Masaru*; Shiogama, Yukihiro*; Atsumi, Hiroyuki; Masumoto, Kazuhiko*; Yasui, Shingo*; Abe, Yasunori*; Furuichi, Mitsuaki*

JNC TJ7440 2000-006, 137 Pages, 2000/02

JNC-TJ7440-2000-006.pdf:3.55MB

no abstracts in English

JAEA Reports

A study of ground water flow in Japan

Hibiya, Keisuke*; *; Shiogama, Yukihiro*; *; Masumoto, Kazuhiko*; Furuichi, Mitsuaki*; Saegusa, Hiromitsu

JNC TN7400 99-004, 314 Pages, 1999/03

JNC-TN7400-99-004.pdf:11.06MB

In order to understand groundwater flow in Japan, it is important to know the hydraulic gradient and the sea / fresh-water boundaly. In particular, the hydraulic gradient is required to estimate very slow groundwater flow at depth. Also, the location of the sea / fresh-water boundary is required to characterize groundwater flow near the coast. In this study, we obtained the above-mentioned data from a number of published papers, and tried to find the suitable method to help evaluating the groundwater flow model.

JAEA Reports

Investigation on sealing in geological disposal

Hibiya, Keisuke*; *; Shiogama, Yukihiro*; Masumoto, Kazuhiko*; Fukazawa, E.*; Taira, K.*; Tanaka, Toshiyuki*; Kondo, Y.*; Yamamoto, M.*; Okutsu, Kazuo*; et al.

PNC TJ1100 97-004, 69 Pages, 1997/02

PNC-TJ1100-97-004.pdf:2.52MB

None

44 (Records 1-20 displayed on this page)