Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamamoto, Nobuyuki; Iwano, Keita*; Namikawa, Tadashi*; Morikawa, Seiji*; Seno, Shoji*; Tabei, Kazuto*; Toida, Masaru*; Yokota, Hideharu
JAEA-Research 2013-003, 252 Pages, 2013/06
JAEA-Research-2013-003.pdf:77.85MB
This study reconsiders rock's mechanical and hydrological parameters based on additional 
data given in this year, and conducts the mechanical-hydrological analysis using the Micromechanics-Based Continuum (MBC) model which can consider the behavior of fracture. The acquired analysis results are compared with actual test data such as drift convergence and hydraulic pressure around the drift. Then, following knowledge is obtained.
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:28.82MBJAEA-Research-2007-065-2.pdf:42.37MBJAEA-Research-2007-065-3.pdf:24.46MBJAEA-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.
Sato, Toshinori; Mikake, Shinichiro; Nakama, Shigeo; Seno, Yasuhiro; Mori, Takayuki*; Iwano, Keita*; Goke, Mitsuo*; Tada, Hiroyuki*
Proceedings of 7th International Conference on Analysis of Discontinuous Deformations (ICADD-7) (CD-ROM), p.245 - 256, 2005/12
Two one-thousand meter deep shafts and research galleries at several levels will be excavated in granite for the Mizunami Underground Research Laboratory (MIU) project. Research on the deep geological environment in this project will provide the basis for Research and Development on geological disposal of high-level radioactive waste. The site of MIU project is located in Mizunami, Gifu, in the central part of the main island of Japan. By July 2003, entrances to the shafts were constructed, and excavation of lower part of shaft entrance was started in March 2004. Current status (September 2005) of construction is excavation of the shafts to a depth of 150 m has been done. Mechanical investigations including hydraulic fracturing test and laboratory tests on core samples were performed, and numerical analysis using continuous model and discontinuous model; MBC (Micro-mechanics based continuum model), Crack tensor model and FRACOD (fracture propagation code), were also performed to predict mechanical stability of openings and support systems, and rock mass behavior around openings. In this analysis EDZ (Excavation Damaged Zone) due to blasting and excavation step were considered in same cases. This paper describes the current status of Mizunami Underground Research Laboratory for crystalline rock and the results of prediction for rock mass behavior around the deep underground openings using some analytical methods. Measurements during shaft sinking and future plan of investigations in the URL are also describes in this paper.
Mori, Takayuki*; Morikawa, Seiji*; Tabei, Kazuto*; Iwano, Keita*; Nakajima, Makoto*
JNC TJ7400 2005-080, 216 Pages, 2005/03
JNC-TJ7400-2005-080.pdf:35.16MB
As a first step of Mizunami Underground Research Laboratory Plan (MIU plan), through the laboratory and borehole in-situ tests, JNC Tono Geoscience Center plans to constitute the comprehensive geological model and predicts the rock behaviors in excavating the shaft and gallery. These model and results leads to be reflected by the next step research projects.So far, the first step of MIU plan is coming to final stage, and the second step will start at next year in which the in-situ researches are planned through the excavation. In this study, the comprehensive geometrical model was drawn out through the first step data, and MBC model analysis was carried out to predict the rock mass behavior around the shaft and gallery. The following results are obtained. (1) With MIZ-1 borehole core, artificial joints, which are assumed to be produced by rock blasting, were formed through the Brazilian test. And through the rock shear test for these joints, these mechanical properties were obtained. (2) By examining the MIZ-1 borehole research data, Mizunami site was classified by mechanical and joint properties and the Geomechanical model were made up. (3) Through the MBC model, the shaft and gallery cases were analyzed which depend on the rock mass classification, Excavation Damaged Zone, and the direction of the galleries. These results showed that in most cases, the joint opening were little because of the rock stiffness, but by the existence of high inclined joints, the side wall of the galleries were damaged by the excavation.
Toida, Masaru*; Suyama, Yasuhiro*; Inaba, Takeshi*; Sasakura, Takeshi*; Atsumi, Hiroyuki*; Tanaka, Toshiyuki*; Kobayashi, Ichizo*; Iwano, Keita*; Furuichi, Mitsuaki*
JNC TJ7400 2004-017, 521 Pages, 2004/02
JNC-TJ7400-2004-017.pdf:96.64MB
"Geoscientific research" at Tono is developing site investigation, characterization and assessment techniques for understanding of geological environment. Their important themes are to establish a methodology for analyzing uncertainties in heterogeneous geological environment and to develop investigation techniques for reducing the uncertainties efficiently. The current study proposes a new approach where all the possible options in the models and data-sets that cannot be excluded in the light of the evidence available is 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, in turn, supports the design of the following investigation stage to reduce the uncertainties efficiently. In this report the technique has been tested through geological modelling and groundwater analysis with Tono area case based on current knouledge, to demonstrate its applicability. This report summarizes as follows: (1)It is possible to quantify the uncertainties with Tono area case based on current knouledge using the technique. (2)Based on sensitivity analyses, it is possible to support designs of the following investigation stage to reduce the uncertainties efficiently. (3)The methodology of the technique has been developed with Tono area case. (4)The above could evaluate its applicability and propose further issues for synthesis of the methodology.
Mori, Takayuki*; Morikawa, Seiji*; Tabei, Kazuto*; Iwano, Keita*
JNC TJ7400 2004-006, 58 Pages, 2004/02
JNC-TJ7400-2004-006.pdf:9.51MB
JNC Tono Geoscience Center planed a comprehensive geoscientific research program for the construction of an underground research laboratory in order to conduct the research and evaluation of geological environment. So far, based on mechanical data from 1,000-m borehole tests, several numerical analysis models, which consider the behavior of joints in a rock mass, have been applied to this site, and the discontinuous rock behavior around the shafts and galleries has been predicted.However, none of these analyses considered the "Excavation Damaged Zone". In this study, in order to grasp the extent of the Excavation Disturbed Zone, MBC analysis considering the Excavation Damaged Zone was carried out and the following results were obtained. 1.Using several parameters relevant to the rock and joints, a parametric study was performed to verify the effect on and sensitivity of the behavior of the Excavation Disturbed Zone. The results showed that joint frequency and Young's modulus of the rock were much effective parameters. 2.Based on the parametric study, several analyses for shaft and gallery were conducted. As the joint density increased and the area of the Excavation Damaged Zone expanded, the joint opening area increased and the equivalent shear stiffness decreased. 3.Two contrasting cases were also analyzed: one was assumed that pre-existing joints progress in the Excavation Damaged Zone, and the other assumed that joints tangential to the excavation wall are generated in the Excavation Damaged Zone. It was found that Excavation Damaged Zone tends to be larger in the former case than the latter case. 4.From these results, prediction analysis for Excavation Disturbed Zone considering the Excavation Damaged Zone was found to be practical. Through the in-situ monitoring data for shafts and galleries, the validity of these analyses will be verified.
Sanada, Hiroyuki; Sugita, Yutaka; Kunimaru, Takanori; Iwano, Keita*; Morikawa, Seiji*; Seno, Shoji*; Namikawa, Tadashi*
no journal, ,
no abstracts in English
Yabuuchi, Satoshi; Kunimaru, Takanori; Iwano, Keita*; Morikawa, Seiji*; Namikawa, Tadashi*
no journal, ,
no abstracts in English
Ishibashi, Masayuki; Sasao, Eiji; Nakajima, Makoto*; Atsumi, Hiroyuki*; Onoe, Hironori; Saegusa, Hiromitsu; Kawabata, Junichi*; Masumoto, Kazuhiko*; Seno, Shoji*; Iwano, Keita*
no journal, ,
no abstracts in English
Masumoto, Kazuhiko*; Atsumi, Hiroyuki*; Iwano, Keita*; Nakajima, Makoto*; Seno, Shoji*; Kawabata, Junichi*; Saegusa, Hiromitsu; Onoe, Hironori; Sawada, Atsushi
no journal, ,
no abstracts in English
Iwano, Keita*; Atsumi, Hiroyuki*; Nakajima, Makoto*; Masumoto, Kazuhiko*; Seno, Shoji*; Kawabata, Junichi*; Onoe, Hironori; Saegusa, Hiromitsu; Sawada, Atsushi
no journal, ,
no abstracts in English
Atsumi, Hiroyuki*; Nakajima, Makoto*; Iwano, Keita*; Masumoto, Kazuhiko*; Seno, Shoji*; Kawabata, Junichi*; Ishibashi, Masayuki; Sasao, Eiji; Hosoya, Shinichi*
no journal, ,
no abstracts in English
Atsumi, Hiroyuki*; Iwano, Keita*; Seno, Shoji*; Masumoto, Kazuhiko*; Kawabata, Junichi*; Saegusa, Hiromitsu; Onoe, Hironori
no journal, ,
no abstracts in English
Hosoya, Shinichi*; Suzuki, Kazushige*; Ishibashi, Masayuki; Sawada, Atsushi; Atsumi, Hiroyuki*; Iwano, Keita*
no journal, ,
no abstracts in English