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Sato, Toshinori; Sanada, Hiroyuki; Tanno, Takeo*
JAEA-Review 2014-049, 34 Pages, 2015/02
JAEA-Review-2014-049.pdf:26.38MB
This report presents the results of following rock mechanical investigations conducted in FY 2013. In-situ stress measurements using Compact Conical-ended Borehole Overcoring Technique were performed at the - 500m stage. Measurement system for rock mass displacement using optical fiber was installed at the - 500m stage as one of the reflooding test. Study on the modeling based on equivalent continuum model was continued. Phenomenological study and theoretical study on long-term behavior of crystalline rock were continued. Additionally, joint research, "Study on estimation of in-situ rock stress based on the results of various measurements" with Tokai University was also performed.
Sanada, Hiroyuki; Sato, Toshinori; Tanno, Takeo*; Hikima, Ryoichi*; Tada, Hiroyuki*; Kumasaka, Hiroo*; Ishii, Takashi*; Sakurai, Hideyuki*
JAEA-Research 2014-006, 124 Pages, 2014/06
JAEA-Research-2014-006.pdf:11.26MB
Japan Atomic Energy Agency has been implementing the Mizunami Underground Research Laboratory (MIU) Project in order to develop the comprehensive investigation techniques for the geological environment and the engineering techniques to construct a deep underground laboratory in crystalline rock. In the rock mechanical study in the MIU Project, the development of the evaluation method for the excavation damaged zone due to excavation of shafts and research galleries is one of the important issues. In this report, crack tensor was calculated using the tunnel wall mapping and rock mechanical test results in the shaft and research galleries in the MIU. Two dimension excavation analysis was conducted at the Ventilation Shaft and GL -500 m Sub Stage using the calculated crack tensor at GL -500 m. Based on calculated crack tensor at GL 500 m, validation of the crack tensor at GL -500 m estimated during Phase I was verified. Relative error of crack tensor was calculated in order to examine variation of relative error to the scale of observation areas.
Sato, Toshinori; Tanno, Takeo*; Hikima, Ryoichi*; Sanada, Hiroyuki
JAEA-Review 2014-009, 60 Pages, 2014/05
JAEA-Review-2014-009.pdf:26.89MB
This report presents the following FY2012 activities undertaken to achieve the above goals. (1) In-situ stress measurements using Compact Conical-ended Borehole Overcoring Technique at the - 300m stage, (2) In-situ stress measurements using core-based methods at the - 500m stage, (3) Laboratory tests using core samples from boreholes drilled at the - 500m stage, (4) Study on the modeling based on equivalent continuum model, (5) Phenomenological study on long-term behavior, (6) Theoretical study for estimating long-term behavior, (7) Application of specific energy for evaluation of in-situ rock mass properties, (8) Study on estimation of in-situ rock stress based on the results of various measurements.
Ichikawa, Yasuaki*; Kimoto, Kazushi*; Sato, Toshinori; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki
JAEA-Research 2013-045, 69 Pages, 2014/03
JAEA-Research-2013-045.pdf:9.51MB
Rock mass is a complex material including several classes of discontinuities and inhomogeneous/anisotropic minerals. If observing rock samples, we know that crystalline rock is a complex of minerals, grain boundaries and microcracks. In this study, the series of experiments were managed by a flow-through type changing temperature, pH and applied stress. Attenuation of ultrasonic waves in rock is investigated experimentally using an intact but coarse-grained granite core sample. For ultrasonic measurements, piezoelectric transducers are used in a through-transmission mode. With the estimated response function, phase and amplitude spectra of the transmitted ultrasonic waves are investigated quantitatively to evaluate the attenuation and change in travel time.
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.
Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi*; Tanno, Takeo*; Sanada, Hiroyuki; Onoe, Hironori; et al.
JAEA-Review 2013-050, 114 Pages, 2014/02
JAEA-Review-2013-050.pdf:19.95MB
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). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in fiscal year 2012. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2012, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.
Tanno, Takeo*; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi*
JAEA-Research 2013-044, 257 Pages, 2014/02
JAEA-Research-2013-044.pdf:44.45MB
In the rock mechanical investigations, the research aims at "Characterization of geological environment in the Excavation Disturbed Zone (EDZ)" from the viewpoint of safety assessment. For the research, the specific data of the EDZ. The research also aims at "Characterization of geomechanical stability around tunnel " from the viewpoint of design and construction of underground facilities. This report presents the results of following rock mechanical investigations conducted at the GL.-300m and GL.-400m Level of Research Galley. (1) Laboratory tests using core and block samples obtained at the GL.-300m and GL.-400m Level of Research Galley, (2) Measurement of Compact Conical-ended Boerhole Overcoring (CCBO) method at the GL.-300m Level of Research Galley, (3) In-situ stress measurements using core-based methods at the GL.- 300m Stage.
Hama, Katsuhiro; Mikake, Shinichiro; Nishio, Kazuhisa; Sasao, Eiji; Iwatsuki, Teruki; Takeuchi, Ryuji; Matsuoka, Toshiyuki; Tanno, Takeo*; Onoe, Hironori; Ogata, Nobuhisa; et al.
JAEA-Review 2013-044, 37 Pages, 2014/01
JAEA-Review-2013-044.pdf:6.36MB
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host crystalline rock at Mizunami City in Gifu, central Japan. The project consists of major research areas, "Geoscientific Research", and proceeds in three overlapping phases, "Phase I: Surface-based investigation Phase", "Phase II: Construction Phase" and "Phase III: Operation Phase". The present report summarizes the research and development activities planned for fiscal year 2013 based on the MIU Master Plan updated in 2010.
Fukui, Katsunori*; Hashiba, Kimihiro*; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Sato, Toshinori
JAEA-Research 2013-031, 52 Pages, 2013/12
JAEA-Research-2013-031.pdf:4.06MB
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. This report describes the results of the activities in fiscal year 2012. In Chapter 1, we provide an overview and the background to this study. In Chapter 2, the results of a long-term creep test on Tage tuff, started in fiscal year 1997 are described. In Chapter 3, the experimental results concerning the loading-rate dependency of strength were examined to understand the time-dependency of rock. In Chapter 4, the stability of tunnels, around which rock stress is larger than that around a circular tunnel, were examined to obtain useful information on the future plan for 
tests in the underground research laboratory.
Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; et al.
JAEA-Review 2013-018, 169 Pages, 2013/09
JAEA-Review-2013-018.pdf:15.71MB
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). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in 2011 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2011, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.
Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi*; Yokoyama, Tatsuya*; Shimoyama, Masahiro*
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.255 - 256, 2013/09
rock stresses were measured by Compact Conical-ended Borehole Overcoring (CCBO) technique in the 300m depth gallery at the Mizunami Underground Research Laboratory and the measurement results were evaluated using a conventional method and a new test of strain sensitivity method. To compare the rock stress evaluated by both methods, the new test of strain sensitivity method resulted in more accurate evaluation than the conventional method, because of its improved stress deviations.
Sato, Toshinori; Tanno, Takeo; Sanada, Hiroyuki; Yokoyama, Tatsuya*; Shimoyama, Masahiro*
Heisei-25 Nendo (2013 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.257 - 258, 2013/09
Japan Atomic Energy Agency is operating underground research laboratory projects in order to establish a firm scientific basis for safe geological disposal of HLW. One of these is the Mizunami Underground Research Laboratory (MIU) project focused on crystalline rock. In situ stress measurement by Compact Conical-ended Borehole Overcoring (CCBO) are conducted to understand in situ stress state at 300 m depth.
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
stress measurement in the Mizunami Underground Research Laboratory, JapanSato, Toshinori; Tanno, Takeo; Hikima, Ryoichi*; Sanada, Hiroyuki; Kato, Harumi*
Proceedings of 6th International Symposium on In-situ Rock Stress (RS 2013) (CD-ROM), p.354 - 359, 2013/08
Japan Atomic Energy Agency is operating underground research laboratory projects in order to establish a firm scientific basis for safe geological disposal of HLW. One of these is the Mizunami Underground Research Laboratory (MIU) project focused on crystalline rock. Rock mechanical studies, including 
stress measurements, are being conducted as part of the projects. This paper describes the current status of in situ stress studies conducted in the MIU. Applicability of high-compliance system for hydraulic fracturing was evaluated and the maximum stress values were revised. Core disking was observed with groundwater flow in galleries at the depth of GL.-200m, during the Compact Conical-ended Borehole Overcoring (CCBO) test was adopted. To simultaneously estimate regional stress fields and the elastic modulus of rock mass from in situ stress measurements, back analysis methods based on three-dimensional finite element analysis and the boundary element method were developed.
Aydan, 
.*; Sato, Toshinori; Hikima, Ryoichi*; Tanno, Takeo
Proceedings of 6th International Symposium on In-situ Rock Stress (RS 2013) (CD-ROM), p.360 - 369, 2013/08
There are various indirect stress inference techniques utilizing borehole breakouts, fault striations and earthquake focal mechanism solutions. Recently, a new stress inference technique utilizing damage zone around blastholes has been proposed and applied to several sites in Japan and Turkey. This method has been utilized in Mizunami Underground Research Laboratory (MIU) used to infer the stress state from the damage around blasted holes. The inferences are compared with in-situ stress measurements and also inferences from other indirect stress inference techniques such as fault striation, earthquake focal mechanism solutions. In this article the studies undertaken so far have been presented and the possibility of the BHD method as an effective indirect tool for actual engineering applications has been discussed when extensive network of underground openings have to be excavated.
Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; Matsui, Hiroya; Sato, Toshinori
JAEA-Review 2013-017, 52 Pages, 2013/07
JAEA-Review-2013-017.pdf:4.87MB
This report presents the following FY2011 activities undertaken to achieve the above goals. (1) Stress Measurements using Core-based Methods on the - 400 m Stage (2) Laboratory tests using Cores and Block samples (3) Literature survey for planning of experiments in Phase III (4) Application of specific energy for evaluation of rock mass properties (5) Study on estimation of rock stress with results of various measurements.
Sanada, Hiroyuki; Hikima, Ryoichi; Tanno, Takeo; Sato, Toshinori; Goke, Mitsuo*; Tada, Hiroyuki*; Kumasaka, Hiroo*
Proceedings of ITA-AITES World Tunnel Congress 2013 (WTC 2013)/39th General Assembly, p.855 - 860, 2013/05
Japan Atomic Energy Agency (JAEA) has been implementing the Mizunami Underground Research Laboratory (MIU) Project for the R&D of geological disposal of High-level Radioactive Waste (HLW) in granite. The MIU Project has been divided into three overlapping phases: Surface-based Investigation Phase (Phase I), Construction Phase (Phase II), and Operation Phase (Phase III). In this paper, FEM analysis using crack tensor theory at the MIU was carried out in order to estimate deformation around the horizontal tunnel for investigations and construction during Phase III, and to confirm the validity of FEM analysis results including parameter settings using fracture information from the vertical borehole drilled during Phase I. The relationship between statistical observations on tunnel walls and pilot boreholes was used to estimate the crack tensor for the investigated area. FEM analysis in this work described the increase of stress in concrete liners due to decrease of Young's Modulus compared to Phase I. Since investigations during Phase II could effectively detected high angle fractures, which couldn't be satisfactorily detected during Phase I, the crack tensor was improved using the Phase II results. Predictions and applicability of the analysis method are to be confirmed with in situ experiments during Phase III.
stress determination at the Mizunami Underground Research Laboratory, JapanSanada, Hiroyuki; Hikima, Ryoichi; Tanno, Takeo; Matsui, Hiroya; Sato, Toshinori
International Journal of Rock Mechanics and Mining Sciences, 59, p.50 - 56, 2013/04
Times Cited Count：6 Percentile：41.45(Engineering, Geological)In this paper, application of DSCA to the Toki Granite in the region around the MIU is described. The purpose of this study is to confirm the reliability of DSCA in characterising crystalline rocks and to understand stress conditions around the MIU. For verification of in situ stress measurement results obtained in this study, they were compared to in situ stress measurement results from hydraulic fracturing studies and regional stresses estimated from stress indicators such as triangulation etc. in the Tono region of Central Japan. Based on the comparisons carried out in this study acquired by DSCA, the maximum principal stress direction in the MIU area was estimated to vary from N to W, which corresponded with stress indicators. Principal stress ratios decreased with depth in the region, with the exception of stresses in a fault zone.
Sato, Toshinori; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Kato, Harumi*
Journal of MMIJ, 129(2,3), p.59 - 64, 2013/02
Japan Atomic Energy Agency has been conducting stress measurements by overcoring method, to aiming establish a firm scientific basis for safe geological disposal. Core disking is observed where rock stress measurements are performed by compact conical-ended borehole overcoring technique in the depth of 300 m from the surface at the Mizunami Underground Research Laboratory. In this report, failure initiation of core disking is discussed.
Tanno, Takeo; Sato, Toshinori; Sanada, Hiroyuki; Hikima, Ryoichi; Kumasaka, Hiroo*; Tada, Hiroyuki*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.109 - 113, 2013/01
The crack tensor model which is a kind of equivalent continuum model has been studied in rock mechanical investigation in the MIU. The fractured rock mass is modeled as the elastic continuum model with this crack tensor. In this study, this crack tensor based on the geological observation in the MIU project was calculated, and REV (Representative Elementary Volume) in the ventilation shaft and -300m access/research gallery was studied based on the relative error of this crack tensor. As a result, the convergence of the relative error was faster in the -300m access/research gallery than in the ventilation shaft.
