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Shimo, Michito*; Kumamoto, So*; Tsuyuguchi, Koji; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya
JAEA-Research 2012-043, 98 Pages, 2013/03
JAEA-Research-2012-043.pdf:26.71MB
One of the goals of the Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding the deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for hydrogeological model and groundwater flow simulation technique, have to be established. As a result of this study, the significant hydrogeological structures around the MIU Construction Site were estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts around the MIU Construction Site caused by the MIU facilities construction were predicted. The effect of pre-grouting to the MIU facilities was also confirmed.
Shimo, Michito*; Kumamoto, So*; Kosaka, Hiroshi; Onoe, Hironori; Saegusa, Hiromitsu; Mizuno, Takashi; Oyama, Takuya
JAEA-Research 2012-004, 126 Pages, 2012/04
JAEA-Research-2012-004.pdf:14.3MB
One of the goals of Mizunami Underground Research Laboratory (MIU) Project is to develop technical basis for investigation, analysis and evaluation technologies for understanding deep underground geological environment in various scales. Understanding groundwater flow system is one of the important issues in the project, and to achieve this purpose, technologies for a hydrogeological model and the groundwater flow simulation technique, have to be established. In this study, hydrogeological modeling and groundwater flow simulations have been carried out in order to predict hydraulic and geochemical impacts around the MIU Construction Site and inflow rate into the MIU facilities. As a result of this study, the significant hydrogeological structures could be estimated. The inflow rate into the MIU facilities and hydraulic and geochemical impacts with the MIU facilities construction could be predicted. The effect of pre-grouting to the MIU facilities could be also confirmed.
Shimo, Michito*; Kumamoto, So*; Onoe, Hironori; Saegusa, Hiromitsu
JAEA-Research 2011-017, 132 Pages, 2011/09
JAEA-Research-2011-017.pdf:9.55MB
In this study, hydrogeological modeling and groundwater flow simulations on the Local scale area have been carried out in order to predict hydraulic impacts around the MIU Construction Site and inflow rate into the MIU facilities using the result of Surface-based Investigation phase (Phase 1), the data of hydraulic responses in monitoring boreholes, inflow rate into the MIU facilities and the result of pilot borehole investigation in Construction phase (Phase 2). As a result of this study, the significant hydrogeological structures around the MIU Construction Site could be estimated. The inflow rate into the MIU facilities and hydraulic impacts around the MIU Construction Site with the MIU facilities construction could be predicted. The effect of pre-grouting to the MIU facilities could be also confirmed.
Shimo, Michito*; Kumamoto, So*; Ito, Akira*; Karasaki, Kenji*; Sawada, Atsushi; Oda, Yoshihiro; Sato, Hisashi
JAEA-Research 2010-040, 57 Pages, 2010/11
JAEA-Research-2010-040.pdf:5.12MB
In safety analysis of geological disposal of the high-level nuclear waste, it is important to evaluate appropriately the mass transport characteristics of the bedrock as the natural barrier. Especially, it has been found that the porosity of the rock matrix is high and fractured zones are developing and therefore the mass transport characteristics will be the mixture of those for porous media and the fractured media. In this work, we conducted, (1) a study on the method to mine out the rock block sample of tens of-centimeter to maximum 1 m scale, (2) a study on a method of the tracer test using a rock block sample and a series of scoping analysis. We also examined the uncertainty associated the hydrogeological model using a method combining a forward and inverse analysis, based on the various type of data sets obtained at Horonobe site, such as the temperature distribution and hydraulic head and salinity distribution.
Shimo, Michito*; Kumamoto, So*; Ito, Akira*; Karasaki, Kenji*; Sawada, Atsushi; Oda, Yoshihiro; Sato, Hisashi
JAEA-Research 2009-060, 70 Pages, 2010/03
JAEA-Research-2009-060.pdf:14.26MB
It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground appropriately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. In this study the following three tasks were carried out: (1) laboratory hydraulic and tracer experiments using the rock cores of Wakkanai formation, (2) a study on the tracer test and sampling technique for the larger scale, (3) a study on the reduction technique of uncertainty of the hydrogeological models using data from surface-based investigation. On the block scale tracer test technique, the sampling technique using wire saw and tracer test technique using block samples were suggested. As for the reduction technique of uncertainty of the hydrogeological model, availability of the information other than pressure data, such as the temperature and salinity and all, were presented.
Shimo, Michito*; Kumamoto, So*; Karasaki, Kenji*; Sato, Hisashi; Sawada, Atsushi
JAEA-Research 2008-101, 70 Pages, 2009/03
JAEA-Research-2008-101.pdf:7.03MB
It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground. The fractures might dominate flow and transport even though it is soft sedimentary rocks. In this study the following three tasks were carried out. Firstly, non-sorbing tracer experiments were carried out. The obtained breakthrough curve was interpreted and mass transport parameters, such as longitudinal dispersivity, matrix diffusion coefficient, transport aperture, were obtained. Secondary, several cases mass transport simulations using single fracture model that the hydraulic aperture, transport aperture, and porosity is different were performed to study on the influence that a difference of the aperture and porosity gives a mass transport in the fractured sedimentary rocks. Finally, groundwater flow was simulated to estimate the flow direction and recharge from the surface using the temperature distribution data obtained in Horonobe boreholes.
Kumamoto, So*; Shimo, Michito*; Saegusa, Hiromitsu; Oyama, Takuya
Dai-38-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.281 - 286, 2009/01
The Mizunami Underground Research Laboratory is being constructed by Japan Atomic Energy Agency in the Cretaceous Toki Granite in the Tono area, Central Japan. During construction, the information needed for testing and revising the hydrogeological model has been obtained. During shaft excavation, pumping of groundwater from the shaft has to be halted and the water level in shaft was recovered for the improvement of facility for treatment of discharged groundwater. This period was divided into three major phases, such as excavation, recovery and discharging phases, and hydraulic behavior in the phases was considered as a large-scale pumping test. In this study, model testing and calibration using the data of inflow volume and hydraulic behavior observed in these three phases have been carried out.
Saegusa, Hiromitsu; Shimo, Michito*; Kumamoto, So*; Onoe, Hironori; Takeuchi, Ryuji; Takeuchi, Shinji; Oyama, Takuya
Proceedings of 36th International Association of Hydrogeologists Congress 2008 (IAH 2008) (CD-ROM), 10 Pages, 2008/10
One of the main goals of the Mizunami Underground Research Laboratory project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. Hydrogeological investigations using a stepwise manner have been carried out to obtain information on important properties. Hydrogeological modeling and groundwater flow simulations, which is for estimations of volume of inflow into underground tunnels and impact of construction of underground facilities on water table and hydraulic pressure, have been carried out by synthesizing these investigation results. From the study, the uncertainty of the hydrogeological model was evaluated and the main issues for further investigations were identified. Also, hydrogeological modeling and groundwater flow simulation using the data of hydraulic responses due to shaft sinking have been carried out in order to test/revise the models constructed in Phase I. These results are introduced in this paper.
Shimo, Michito*; Kumamoto, So*; Karasaki, Kenji*; Sawada, Atsushi; Maekawa, Keisuke; Sato, Hisashi
JAEA-Research 2008-029, 95 Pages, 2008/03
JAEA-Research-2008-029.pdf:4.51MB
It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground accurately. The objective of this study is to expand the data of flow and mass transport properties in fractured sedimentary rocks, and to estimate these properties in larger scale rocks, such as in situ test scale, using the results of the laboratory tests and the borehole investigations. This study was carried out under the following three tasks: (1) laboratory hydraulic and tracer experiments using the rock specimens of Koetoi formation obtained at underground research facility under construction in the Horonobe area, (2) a numerical study on the influence that a difference of the groundwater flow velocity in the fractures gives a mass transport in the fractured sedimentary rocks, (3) a numerical study on the contributing factors to groundwater flow such as effect of low permeability layers.
Shimo, Michito*; Kumamoto, So*; Maekawa, Keisuke
JAEA-Research 2007-016, 141 Pages, 2007/03
JAEA-Research-2007-016.pdf:20.36MB
It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground accurately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. The objective of this study is to establish a conceptual model for flow and mass transport in fractured soft sedimentary rock. In previous study, a series of laboratory hydraulic and tracer tests and numerical analyses were carried out using sedimentary rock specimens obtained from Koetoi and Wakkanai formation. Single natural fractured cores and rock block specimen were used for the tests and analyses. The results indicated that the matrix diffusion played an important role for mass transport in the fractured soft sedimentary rocks. In this study, the following two tasks were carried out: (1) laboratory hydraulic and tracer experiments of rock cores of koetoi and Wakkanai formation obtained at HDB-9, HDB-10 and HDB-11 boreholes and a rock block specimen, Wakkanai formation, obtained at an outcrop in the Horonobe area, (2) a numerical study on the conceptual model of flow and mass transport through fractured soft sedimentary rocks. Non-sorbing tracer experiments using naturally fractured cores and rock block specimens were carried out. Potassium iodide was used as a tracer. The obtained breakthrough curves were interpreted and fitted by using a numerical simulator, and mass transport parameters, such as longitudinal dispersivity, matrix diffusion coefficient, transport aperture, were obtained. Mass transport simulations using a fracture network model, a continuum model and a double porosity model were performed to study the applicability of continuum model and double porosity model for transport in fractured sedimentary rock.
Kumamoto, So*; Shimo, Michito*; Kurikami, Hiroshi
Chikasui Ryudo Kaiseki To Moderuka Ni Kansuru Shimpojium Happyo Rombunshu, p.43 - 50, 2007/01
no abstracts in English
Kumamoto, So*; Shimo, Michito*; Saegusa, Hiromitsu; Onoe, Hironori
Dai-36-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.287 - 292, 2007/01
no abstracts in English
Kurikami, Hiroshi; Kunimaru, Takanori; Yabuuchi, Satoshi; Seno, Shoji; Shimo, Michito*; Kumamoto, So*
Proceedings of 2nd International Conference on Coupled T-H-M-C Processes in Geo-systems; Fundamentals, Modeling, Experiments and Applications (GeoProc 2006), p.584 - 589, 2006/05
no abstracts in English
Shimo, Michito*; Kumamoto, So*
JNC TJ5410 2005-003, 40 Pages, 2005/03
JNC-TJ5410-2005-003.pdf:2.27MB
The objective of this study is to understand hydraulic and mass transeport properties of sedimentary rock at shallow depth. A series of laboratory hydraulic and tracer tests using sedimentary rock specimens in subsurface layer obtained from shallow boreholes. The obtained hydraulic conductivities varied between 8.5 10-10 - 2.0 10-9m/s. The effective diffusion coeficients obtained from the through diffusion test were 1.5 10-10 - 3.5 10-10m/s
Shimo, Michito*; Yamamoto, Hajime*; Kumamoto, So*; Fujiwara, Yasushi*; Ono, Makoto*
JNC TJ5400 2004-004, 120 Pages, 2005/02
JNC-TJ5400-2004-004.pdf:78.08MBJNC-TJ5400-2004-004(errata).pdf:0.08MB
The Horonobe underground research project has been carried out by Japan Nuclear Cycle Development Institute to study the geological environment of sedimentary rocks in deep underground. The objectives of this study are to develop a geological environment model, which incorporate current findings and latest data obtained through the geological, geophysical, and borehole investigations at Horonobe site, and to predict the hydrological and geochemical impacts caused by the URL shaft excavation to the surrounding area.
Shimo, Michito*; Kumamoto, So*
JNC TJ8400 2004-012, 121 Pages, 2004/02
JNC-TJ8400-2004-012.pdf:22.33MB
The objective of this study is to establish a conceptual model for flow and transport in fractured soft sedimentary rock. In this fiscal year, this study was carried out for two tasks: (1) classification of soft sedimentary rocks by literature survey, (2) laboratory experiments on the flow and mass transport using rock specimens obtained at HDB-6 and 7 borehole in Horonobe Deep Underground Research Center. Classification of soft sedimentary rocks is carried out using a database of permeability collected by JNC. In laboratory experiments, core samples of the Tertiary siliceous mud rock obtained from the HDB-6 and 7 borehole, which was excavated in the Horonobe area in this year, were studied. The matrix porosity of intact cores measured by wet and dry weight was ranging from 33% to 41%. The hydraulic conductivities of rock matrix determined by the transient pulse test were in an order of 10-12 m/s. The effective diffusion coefficients obtained from the through diffusion test were 0.8 to 2.5
10-11 m2/s. This suggested that, in these cores, the flow in the rock matrix is not significant comparing with the flow in fractures, and the matrix diffusion from fractures into rock matrix should cause a significant effect to the mass transport phenomenon. Non-sorbing tracer experiment was conducted in fractured cores. As a tracer, potassium iodide solution was injected at a constant rate and the tracer concentration change during injection was observed at the outlet. The obtained breakthrough curve was interpreted and fitted by using a numerical simulator for flow and mass transport called FRAC3DVS (Therrien et al., 1999), and finally, mass transport parameters are obtained. The result indicates that the matrix diffusion plays an important role for mass transport in the fractured soft sedimentary rocks.
Shimo, Michito*; Kumamoto, So*
JNC TJ8400 2004-011, 198 Pages, 2004/02
JNC-TJ8400-2004-011.pdf:29.86MB
The objective of this study is to establish a conceptual model for flow and transport in fractured soft sedimentary rock.In this fiscal year, this study was carried out for two tasks: (1) classification of soft sedimentary rocks by literature survey, (2) laboratory experiments on the flow and mass transport using rock specimens obtained at HDB-6 and 7 borehole in Horonobe Deep Underground Research Center.Classification of soft sedimentary rocks is carried out using databases of permeability of rock collected by JNC. In laboratory experiments, core samples of the Tertiary siliceous mud rock obtained from the HDB-6 and 7 borehole, which was excavated in the Horonobe area in this year, were studied. The matrix porosity of intact cores measured by wet and dry weight was ranging from 33% to 41%. The hydraulic conductivities of rock matrix determined by the transient pulse test were in an order of 10-12 m/s. The effective diffusion coefficients obtained from the through diffusion test were 0.8 to 2.510-11 m2/s. This suggested that, in these cores, the flow in the rock matrix is not significant comparing with the flow in fractures, and the matrix diffusion from fractures into rock matrix should cause a significant effect to the mass transport phenomenon.Non-sorbing tracer experiment was conducted in fractured cores. As a tracer, potassium iodide solution was injected at a constant rate and the tracer concentration change during injection was observed at the outlet. The obtained breakthrough curve was interpreted and fitted by using a numerical simulator for flow and mass transport called FRAC3DVS (Therrien et al., 1999), and finally, mass transport parameters are obtained. The result indicates that the matrix diffusion plays an important role for mass transport in the fractured soft sedimentary rocks.
Shimo, Michito*; Yamamoto, Hajime*; Kumamoto, So*
JNC TJ8400 2003-036, 46 Pages, 2003/02
JNC-TJ8400-2003-036.pdf:0.99MB
The objective of this study is to establish a conceptual model for flow and transport in fractured soft sedimentary rock. In this fiscal year, this study was carried out for two tasks: (1) classification of soft sedimentary rocks by literature survey, (2) laboratory experiments on the flow and mass transport using rock specimens obtained at HDB-4 borehole in Horonobe Deep Underground Research Center.Classification of soft sedimentary rocks is carried out using two databases of rock properties collected by JNC and Geological Survey of Japan. In laboratory experiments, core samples of the Tertiary siliceous mud rock obtained from the HDB-4 borehole, which was excavated in the Horonobe area in this year, were studied. The matrix porosity of intact cores measured by wet and dry weight was ranging from 33% to 41%. he hydraulic conductivities of rock matrix determined by the transient pulse test were in an order of 10-11 m/s. The effective diffusion coefficients obtained from the "through diffusion test" were 0.8 to 2.510-11 m2/s. This suggested that, in these cores, the flow in the rock matrix is not significant comparing with the flow in fractures, and the matrix diffusion from fractures into rock matrix should cause a significant effect to the mass transport phenomenon. Non-sorbing tracer experiment was conducted in fractured cores. As a tracer, potassium iodide solution was injected at a constant rate and the tracer concentration change during injection was observed at the outlet. The obtained breakthrough curve was interpreted and fitted by using a numerical simulator for flow and mass transport called FRAC3DVS (Therrien et al., 1999), and finally, mass transport parameters are obtained. The result indicates that the matrix diffusion plays an important role for mass transport in the fractured soft sedimentary rocks.
Shimo, Michito*; Yamamoto, Hajime*; Kumamoto, So*
JNC TJ8400 2003-028, 135 Pages, 2003/02
JNC-TJ8400-2003-028.pdf:3.79MB
The objective of this study is to establish a conceptual model for flow and transport in fractured soft sedimentary rock.In this fiscal year, this study was carried out for two tasks: (1) classification of soft sedimentary rocks by literature survey, (2) laboratory experiments on the flow and mass transport using rock specimens obtained at HDB-4 borehole in Horonobe Deep Underground Research Center. Classification of soft sedimentary rocks is carried out using two databases of rock properties collected by JNC and Geological Survey of Japan. In laboratory experiments, core samples of the Tertiary siliceous mud rock obtained from the HDB-4 borehole, which was excavated in the Horonobe area in this year, were studied. The matrix porosity of intact cores measured by wet and dry weight was ranging from 33% to 41%. The hydraulic conductivities of rock matrix determined by the transient pulse test were in an order of 10-11 m/s. The effective diffusion coefficients obtained from the through diffusion test were 0.8 to 2.5x10-11 m2/s. This suggested that, in these cores, the flow in the rock matrix is not significant comparing with the flow in fractures, and the matrix diffusion from fractures into rock matrix should cause a significant effect to the mass transport phenomenon. Non-sorbing tracer experiment was conducted in fractured cores. As a tracer, potassium iodide solution was injected at a constant rate and the tracer concentration change during injection was observed at the outlet. The obtained breakthrough curve was interpreted and fitted by using a numerical simulator for flow and mass transport called FRAC3DVS (Therrien et al., 1999), and finally, mass transport parameters are obtained. The result indicates that the matrix diffusion plays an important role for mass transport in the fractured soft sedimentary rocks.
Shimo, Michito*; Yamamoto, Hajime*; Jo, Mayumi*; Yamagami, Masahito*; Fumimura, Kenichi*; Kumamoto, So*; Igarashi, Takafumi*
JNC TJ7440 2005-083, 991 Pages, 2003/01
JNC-TJ7440-2005-083.PDF:130.74MB
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