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Toida, Masaru*; Atsumi, Hiroyuki*; Nagoya, Kaoru*; Suyama, Yasuhiro*
JNC TJ7440 2005-070, 279 Pages, 2004/03
JNC-TJ7440-2005-070.PDF:22.63MB
no abstracts in English
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.
Toida, Masaru*; Suyama, Yasuhiro*; Shiogama, Yukihiro*; Atsumi, Hiroyuki*; Abe, Yasunori*; Furuichi, Mitsuaki*
JNC TJ7410 2003-004, 351 Pages, 2003/02
JNC-TJ7410-2003-004.pdf:47.52MB
"Geoscientific research" at Tono are developing site investigation and assessment techniques in geological environment. One of their important themes is to establish rational methodology to reduce uncertainties associated with the understanding of geological environment, which often exhibits significant heterogeneity. Purpose of this study is to identify and evaluate uncertainties associated with the understanding of geological environment. Because it is useful to guide designing effective site investigation techniques to reduce the uncertainty. For this, a methodology of the uncertainty analysis concerning the heterogeneous geological environment has been developed. In this report the methodology has also been tested through an exercise attempted in Tono area to demonstrate its applicability. This report summarizes as follows: 1)The exercise shows that the methodology considered 'variability' and 'ignorance' can demonstrate its applicability at three-dimensional case. 2)The exercise shows that the methodology can identity and evaluate uncertainties concerning ground water flow associated with performance assessment. 3)Based on sensitivity analysis, it is possible for the methodology to support designs of the following stage investigations to reduce the uncertainties efficiently.