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Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Tanno, Takeo*; Sanada, Hiroyuki; Sato, Toshinori
JAEA-Research 2013-040, 51 Pages, 2014/03
JAEA-Research-2013-040.pdf:6.86MB
For the research and development about high-level radioactive waste disposal, it is important to evaluate the mechanical stability of the excavation and the long-term behavior of in situ rock. However, from the limited information such as the bowling core before the excavation, it is difficult to evaluate the mechanical properties of in situ rock containing cracks. For this reason, evaluation of rock properties based on Specific Energy using mechanical data from an excavation machine is carried out. This report describes the results of the joint research carried out in FY 2010 to FY 2012.
Hikima, Ryoichi*; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.247 - 248, 2013/08
no abstracts in English
Soma, Nobukazu*; Oikawa, Yasuki*; Hirano, Toru*; Matsui, Hiroya; Asanuma, Hiroshi*
Butsuri Tansa, 66(2), p.69 - 83, 2013/04
We have studied a reflection imaging technique in which passive seismic signals from other construction activity such as drilling noise are used as a wave source in order to develop a low-cost measurement method inside underground gallery. In this paper, we show an application to data sets from Mizunami Underground Research Laboratory of Japan Atomic Energy Agency. The drilling was conducted with a main purpose of extraction rock core samples for rock mechanics research. The three-dimensional reflection imaging results and comparison with well observation are shown in this paper.
Hirano, Toru*; Seno, Yasuhiro*; Hikima, Ryoichi; Matsui, Hiroya
JAEA-Research 2011-019, 51 Pages, 2011/09
JAEA-Research-2011-019.pdf:2.93MB
In order to establish the scientific and technical basis for geological disposal of high-level radioactive waste, Japan Atomic Energy Agency (JAEA) is proceeding with the geoscientific research in the research galleries excavated at the Mizunami Underground Research Laboratory (MIU). One of the scientific and technical objective of this project is to understand the change of geological environment due to excavation of research galleries. The investigation described herein is the measurement of the rock strain / displacement while pre-excavation grouting or excavating of the shaft around the GL.-200m level research gallery.
Hikima, Ryoichi; Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo; Hirano, Toru*; Yamashita, Masayuki*; Ishiyama, Koji*
Heisei-23 Nendo (2011 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.265 - 266, 2011/09
no abstracts in English
Tanno, Takeo; Hirano, Toru*; Matsui, Hiroya
JAEA-Research 2011-013, 59 Pages, 2011/06
JAEA-Research-2011-013.pdf:5.39MB
This report presents the following FY2009 activities undertaken to achieve the above goals. (1) Suitability of Laboratory Tests of Physical and Mechanical Properties on Waste Rock from Excavation of the Shaft, (2) Suitability of the Phase I Rock Mechanical Environment Model, (3) Preliminary Deformation Analysis of Rock Mass around the Underground Facilities, (4) Phenomenological Study on Crystalline Rock for Evaluating Long-term Behavior, (5) Theoretical Study on Crystalline Rock for Evaluating of Long-term Behavior, (6) Fundamental Study on Evaluation Methods of Excavation Distributed Zones. As the result of above 6 activities, suitability of laboratory test and Phase I Rock mechanical Environment Model are confirmed and also methods for EDZ estimation were specified by estimation of in situ stress with core and SWD (Seismic While Drilling).
Ichikawa, Yasuaki*; Choi, J. H.*; Tanno, Takeo; Hirano, Toru*; Matsui, Hiroya
JAEA-Research 2011-007, 91 Pages, 2011/06
JAEA-Research-2011-007.pdf:8.75MB
We first surveyed the classical theories of fracture mechanics, and discussed the subcritical crack growth (SCG), which is observed under less load than the fracture toughness Kc. This SCG is a result of coupled mechanical and chemical effect. The SCG for granite was treated on this basis. We performed pressure dissolution experiments using specimens of single crystal quartz, since the dissolution reaction is engaged with a deformation and failure process of polycrystalline rock. The series of experiments were managed by a flow-through type changing temperature, pH and applied stress. Si concentrations we here measured. We first surveyed the theories of pressure solution. Then we proposed a theory of saluting velocity of quart which accounts for the effects of temperature, chemical (pH), solid pressure and pore pressure.
Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; Mizuno, Takashi; et al.
JAEA-Review 2011-007, 145 Pages, 2011/03
JAEA-Review-2011-007.pdf:16.51MB
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU Project are planned in three overlapping phases; Surface-based Investigation Phase (Phase 1), Construction Phase (Phase 2) and Operation Phase (Phase 3). Currently, the project is under the Construction Phase. This document introduces the results of the research and development in fiscal year 2009, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site and the Shobasama Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration, etc. The goals of the Phase 2 are to develop and revise the models of the geological environment using the investigation results obtained during excavation and determine and assess changes in the geological environment in response to excavation, to evaluate the effectiveness of engineering techniques used for construction, maintenance and management of underground facilities, to establish detailed investigation plans of Phase 3.
Oikawa, Yasuki*; Soma, Nobukazu*; Tosha, Toshiyuki*; Matsui, Hiroya; Hirano, Toru*; Tanno, Takeo; Hikima, Ryoichi
JAEA-Research 2010-048, 45 Pages, 2011/02
JAEA-Research-2010-048.pdf:7.68MB
In excavating a gallery or a shaft in deep underground, an excavation disturbed zone (EDZ) develops around the opening with new cracks due to both stress redistribution and excavation induced damage. The investigation and the evaluation of an EDZ are needed because the changes in rock properties and the EDZ development influence performance assessment of geological disposal and design of the underground structures. However, the in situ investigation of an EDZ is time consuming and costly because investigations are large-scale and required specialized equipment. We conducted a fundamental study for the development of an EDZ investigation method that is easy and inexpensive using the information obtained from only drilling. This report describes the results of the joint research carried out in fiscal year 2008 and fiscal year 2009. In Chapter 1, we provide the overview and the background of this study. In Chapter 2, we discuss the estimation of stress state around the research gallery at a depth of 200m in Mizunami Underground Research Laboratory (MIU) by Acoustic Emission / Deformation Rate Analysis (AE/DRA) method using rock cores obtained from the drilling. In Chapter 3, results of the evaluation of geological structure around the research gallery at a depth of 200m in MIU based on Seismic While Drilling (SWD) method using the vibrations caused by the drilling are described.
Horiuchi, Yasuharu; Hirano, Toru*; Ikeda, Koki; Matsui, Hiroya
Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.242 - 247, 2011/01
Japan Atomic Energy Agency (JAEA) installed the intelligent type strain meters, at G.L-500m depth in pilot boreholes drilled from the 200m level in the ventilation and main shafts of the Mizunami Underground Research Laboratory (MIU). Strain variations due to several events including the excavation itself were monitored and analyzed. Monitoring results indicate that the intelligent type strain meter is able to measure very small fluctuations and detect rock deformation from blasting with 300m vertical separation from the measurement section. The strain meter can detect conditions in the rock mass such as differences in deformability.
Matsui, Hiroya; Tanno, Takeo; Hirano, Toru*; Goke, Mitsuo*; Kumasaka, Hiroo*; Tada, Hiroyuki*; Ishii, Takashi*
JAEA-Research 2010-043, 87 Pages, 2010/12
JAEA-Research-2010-043.pdf:3.99MB
The results are as follows (1) For the ventilation shaft at GL-350m, the crack tensor deformation analysis based on FY2004 work's results showed the calculated displacement was smaller than the measured displacement. A geometrical parameters of fractures in FY2004 work's result was different from one based on geological observation in the shaft. Therefore, the crack tensor of FY2004 work's results seems to be underestimated. (2) Large discontinuities with NE strike and high dipping observed in a shaft were major reason for the difference of crack tensors determined by borehole investigation from surface and geological observations in a shaft. Therefore, the crack tensor for pilot borehole investigation in a shaft was calculated as well and compared with each results. It was found that the fabric tensor is similar with it of geological observation and the vale was medium. (3) The crack tensor around GL-500m was estimated by relation of statistical quantities for fractures between GL-300m and GL-500m. Consequently, the deformation analysis based on the estimated crack tensor showed an increase in convergence and stress in the support system compared to FY2004 work's results.
Okubo, Seisuke*; Hikima, Ryoichi; Hirano, Toru*; Matsui, Hiroya
JAEA-Research 2010-031, 45 Pages, 2010/10
JAEA-Research-2010-031.pdf:1.22MB
Rock shows time-dependent behavior such as creep/relaxation. With respect to high-level radioactive waste disposal, knowledge of the long-term mechanical stability of shafts and galleries excavated in rock are required, not only during construction and operation but also over a period of thousands of years after closure. Therefore, it is very important to understand the time-dependent behavior of rock for evaluating long-term mechanical stability. The purpose of this study is determining the mechanisms of time-dependent behavior of rock by the precise test, observation and measurement, to develop methods for evaluating long-term mechanical stability. In previous work, testing techniques have been established and basic evaluation methods were developed. Recently, some parameters needed for simulation of time-dependent behavior were determined at the Mizunami underground research facilities. However, we did not have enough data to check on the reliability of the evaluation method for these parameters. This report describes the results of the activities in fiscal year 2009. In Chapter 1, we provide an overview and the background to this study. In Chapter 2, the results of the long-term creep test on Tage tuff, started in fiscal year, 1997 are described. In Chapter 3, methods for obtaining parameters of the constitutive equation for rock are reviewed and summarized. The time dependent behavior of Toki granite and Inada granite (40-80 
C) are also summarized based on data obtained prior to the previous fiscal year. In Chapter 4, the FEM analysis implemented with a generalized variable-compliance-type constitutive equation carried out to clarify the long-term behavior of Toki granite is described. Finally, based on the numerical analysis, an in situ testing method is proposed.
Takeuchi, Shinji; Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; et al.
JAEA-Review 2010-029, 28 Pages, 2010/08
JAEA-Review-2010-029.pdf:3.43MB
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). Geoscientific research and the MIU project is planned in three overlapping phases; Surface-based investigation phase (Phase1), Construction phase (Phase2) and Operation phase (Phase3). The project is currently under the construction phase, and the operation phase starts in 2010. This document introduces the research and development activities planned for 2010 fiscal year plan based on the MIU master plan updated in 2010, (1) Investigation plan, (2) Construction plan, (3) Research collaboration plan, etc.
Horiuchi, Yasuharu; Hirano, Toru; Ikeda, Koki; Matsui, Hiroya
JAEA-Technology 2010-017, 122 Pages, 2010/07
JAEA-Technology-2010-017.pdf:35.17MB
JAEA-Technology-2010-017-appendix(CD-ROM).zip:28.63MB
Knowledge of strain variations at an excavation face is important for the prediction of rock bursts and for the application of the appropriate supplementary construction methods for excavation of shafts to great depths. JAEA installed the intelligent type strain meters, at G.L-500m depth in pilot boreholes drilled from the 200m level in the ventilation and main shafts of the Mizunami URL. Strain variations due to several events including the excavation itself were monitored and analyzed. Because of the breakdown of the monitoring system, the data is very short term. Nevertheless, it was possible to do some analysis for the study and important understanding derived from the analysis. Monitoring results indicate that the intelligent type strain meter is able to measure very small fluctuations and detect rock deformation from blasting with 300m vertical separation from the measurement section. The strain meter can detect conditions in the rock mass such as differences in deformability.
Takeuchi, Shinji; Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Hayano, Akira; Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; et al.
JAEA-Review 2010-014, 110 Pages, 2010/07
JAEA-Review-2010-014.pdf:27.34MB
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is developing a geoscientific research project named Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to establish scientific and technological basis for geological disposal of HLW. Geoscientific research at MIU is planned to be carried out in three phases over a period of 20 years; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase. This document presents the following results of the research and development performed in fiscal year 2008, as a part of the Construction Phase based on the MIU Master Plan updated in 2002, (1) Investigation at the MIU Construction Site and the Shobasama Site, (2) Construction at the MIU Construction Site, (3) Research Collaboration.
Tanno, Takeo; Hirano, Toru*; Matsui, Hiroya
Rock Stress and Earthquakes; Proceedings of 5th International Symposium on In-situ Rock Stress (ISRS-5), p.521 - 526, 2010/07
Japan Atomic Energy Agency has developed a method for accurate evaluation of the distributions of actual in-situ stress state at any point using limited results of in-situ stress measurement from surface based investigations. We assumed that the actual stress components are formed by a combination of overburden pressure and the plate tectonic force, and constructed two types of models, the three-dimensional finite element method and the boundary element method that considered the existence of geological heterogeneity, such as variations in rock type and faults. Afterwards, as a validation of these models, we applied this method to in-situ stress state evaluation for some locations around the Mizunami Underground Research Laboratory (MIU).
Hirano, Toru; Seno, Yasuhiro*; Matsui, Hiroya
JAEA-Research 2010-013, 51 Pages, 2010/06
JAEA-Research-2010-013.pdf:42.02MB
Japan Atomic Energy Agency is proceeding with the geoscientific research at the Mizunami Underground Research Laboratory. In this project, developing a conceptual model of the geological environment is one of the scientific and technical objectives. Once excavation of research galleries began, the model could be improved using more detailed information from underground-based investigations. The investigation described here in is the measurement of the rock mechanical properties and initial stress of the rock mass around the GL.-200m level research gallery. The average physical and mechanical properties determined using core from the Toki Granite on this level is consistent with the properties from MIZ-1 testing. In situ stress measurements indicate that the 
1 is 10.6 MPa and horizontal in the NW-SE direction matched to the observations in MIZ-1 at the same depth. This indicates that the surface based investigations in MIZ-1 are valid at this level.
Mizuta, Yoshiaki*; Kaneko, Katsuhiko*; Matsuki, Koji*; Sugawara, Katsuhiko*; Sudo, Shigeaki*; Hirano, Toru; Tanno, Takeo; Matsui, Hiroya
JAEA-Research 2010-011, 35 Pages, 2010/06
JAEA-Research-2010-011.pdf:4.42MB
The best way to know the initial stress clearly is to measure it in the location where a tunnel will be excavated. However, it is difficult to measure a large number of the initial stresses, budgetary considerations notwithstanding, because of the large scale of underground structures like a radioactive waste disposal facility. Therefore we developed a method for determination of initial stress for arbitrary points from limited results of initial stress measurements. This report is a summary of the contract work about this development. At first, we made local scale numerical models of the Tono area. Using these models, we determined the regional stress state from limited initial stress measurements results. Then we applied the regional stress state to boundary conditions of other numerical models and estimated initial stress at arbitrary points. The result is an estimated initial stress that matched the original stress measurement results from the first analytical results.
Hirano, Toru; Seno, Yasuhiro*; Matsui, Hiroya
JAEA-Research 2010-005, 41 Pages, 2010/06
JAEA-Research-2010-005.pdf:3.11MB
Japan Atomic Energy Agency is carrying out a geoscientific research project at the Mizunami, to establish the scientific and technological basis for geological disposal of HLW. The project is currently in Phase II. The Phase II goals are to construct models of the geological environment from all investigation results obtained during the construction. These models describe the geological environment at the construction points that were affected by excavation of the shafts and the galleries. To achieve these goals, we are examing the relationship between scope of investigation and accuracy of data, an assessment of investigation methods, validation of the Phase I geological environment models and construction of block scale geological environment models. As part of these studies, rock mechanical investigations involving both laboratory testing and in situ stress measurements every 100m along the shaft. This report presents the FY2008 activities undertaken to achieve the above goals.
Hirano, Toru; Nakama, Shigeo; Yamada, Atsuo*; Seno, Yasuhiro*; Sato, Toshinori*
JAEA-Research 2010-002, 48 Pages, 2010/06
JAEA-Research-2010-002.pdf:5.92MB
Japan Atomic Energy Agency is advancing the geo-scientific research at the Mizunami Underground Research Laboratory. In Phase II of the research, improvement on the previous conceptual model of the geological environment is one of the objectives. So the additional rock mechanical investigations on the GL.-100m level research gallery was conducted. As a result, the average rock physical and mechanical properties are consistent with the results from MIZ-1 testing. This means that the surface based investigations in MIZ-1 are valid at this level. Almost all in situ stress measurements indicate that the maximum principal stress is oriented in the NW-SE direction and match the observations in MIZ-1 at GL.-200m depth. But the observed stress level is not the expected value extrapolated from the MIZ-1 results. This suggests that the in situ stress has likely been decoupled at the rock boundary located about GL.-150m level between the Toki Lignite-bearing formation and the Toki granite.