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Hiramoto, Masayuki; Kobayashi, Yasushi; Aoyagi, Shigeo*; Miyanomae, Shunichi*
JAEA-Research 2008-013, 62 Pages, 2008/03
JAEA-Research-2008-013.pdf:9.17MB
For improvement of the credibility of evaluation method for the long-term dynamical behavior of near-field rock mass, the influence that swelling pressure caused by buffer material and expansion pressure caused by the erosion of overpack gave long-term stability of near-field rock mass was studied in this report. As a result, because swelling pressure caused by buffer material and expansion pressure caused by the erosion of overpack acted on near-field rock mass as inner pressure, long-term stability of near-field rock mass improved. And it was shown that conventional evaluation method gave results of safe side. But as an exception, when stiffness property of buffer material is large and initial stress of rock mass is small, a possibility that tensile fracture occurred in near field rock mass was shown. In such a case, a possibility that functional decline of artificial barrier happens is concerned, because buffer material flows out into the crack that occurred in rock mass.
Hiramoto, Masayuki; Kobayashi, Yasushi; Aoyagi, Shigeo*; Miyanomae, Shunichi*; Morita, Atsushi*
JAEA-Research 2007-003, 54 Pages, 2007/03
JAEA-Research-2007-003.pdf:3.67MB
For the study on the long-term stability of near-field rock mass, the following studies were carried out in this report. (1) Inspection of applicability of a valuable-compliance-type constitutive equation that used the measurement data of the existing tunnel. (2) Suggestion of the informatization construction that used a valuable-compliance-type constitutive equation (1) FEM model was developed to estimate the time dependet behavior of rock mass surrounding tunnel. The calculated results such as tunnel convergence and the axial force exerted on tunnel support were compared with the measured results in-situ. It was found that the calculated results reasonably well coincided with the measured results. (2) The informatization construction that used a valuable-compliance-type constitutive equation was suggested. This method will be used for disposal ground construction. It will be led to improving reliability of long-term evaluation after closedown.
Matsui, Hiroya; Aoyanagi, Shigeo; Miyanomae, Shunichi*
Dai-41-Kai Jiban Kogaku Kenkyu Happyokai Happyo Koenshu, p.495 - 496, 2006/07
no abstracts in English
Yoshino, Naoto; Miyanomae, Shunichi*; Inoue, Hiroyuki*; Nashimoto, Yutaka*
JNC TJ8400 2005-004, 166 Pages, 2005/02
JNC-TJ8400-2005-004.pdf:4.59MB
In this paper, following two issues were examined and estimated, (1) The influence of near field condition factor to the dynamical behavior of sedimentary soft rock (2) The long term estimation of the dynamical behavior considering the condition of Horonobe area As the study about the influence of near field condition factor to the dynamical behavior of sedimentary soft rock, the thermal factor was focused on and the laboratory tests using test pieces which were sampled in Horonobe area were carried out under the water temperature were 20 degrees and 80 degrees. As a result, the time dependence parameter in variable-compliance-type constitutive-equation could be obtained. And comparison between creep property under 20 degrees and 80 degrees was conducted. In addition, the general properties of sedimentary soft rock under several conditions were identified by the survey of the literature. And the way how to confirm the dynamical properties of sedimentary soft rock with in-situ test were presented. For the study on the short-term and long-term stability of rock surroundig buffer materials, numerical simulations were carried out assuming several conditions. The direction of disposal tunnels and the ratio of rock strength by initial stress were estimated to be the main factor affecting the short-term stability of rock. Time dependency of rock and the stiffness of buffer material were estimated to be the main factor affecting the long-term stability of rock.
Inoue, Hiroyuki*; Yoshino, Naoto; Miyanomae, Shunichi*; Mizutani, Kazuhiko*; Noda, Kenji*
JNC TJ8400 2004-005, 161 Pages, 2004/02
JNC-TJ8400-2004-005.pdf:18.59MB
In this study, the laboratory mechanical tests of sedimentary soft rock sampled at HORONOBE area in HOKKAIDO prefecture were conducted in order to build the confidence of OKUBO model for long term deformation of sedimentary rock. And the stability of rock around tunnel in building under the condition assumed the underground of HORONOBE area was examined by numerical simulation using information of boring data obtained before 2002 year. As a result, authors could obtain many values of parameter in OKUBO model under various conditions. These conditions have the difference of temperature and water saturation. In addition, the life time in creep predicted by OKUBO model could be compared with the real one. And numerical simulations, assuming various conditions such as stiffness of buffer material and yielding of support, had been carried out to evaluate the long-term stability of rock surrounding buffer material. Results show the decreasing tendency of time dependency of rock.