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Funaki, Hironori; Tokiwa, Tetsuya; Ishii, Eiichi; Hatsuyama, Yoshihiro*; Matsuo, Shigeaki*; Tsuda, Kazuyasu*; Koizumi, Akira*; Ishikawa, Taiki*; Daijo, Yuichi*; Sugiyama, Kazutoshi*
JAEA-Data/Code 2008-013, 65 Pages, 2008/08
JAEA-Data-Code-2008-013.pdf:6.38MB
We conducted geological investigation of the pilot borehole of the ventilation shaft in Horonobe during October 2007 and March 2008. This report describes the field operations (core description, core photograph, and core sampling) and laboratory measurements (modal analysis and X-ray diffraction analysis), equipments as well as processing procedures, and shows the obtained results. The information obtained from this investigation will be reflected in spring water control plan on shaft excavation and additional plan of drainage treatment facilities.
Ishii, Eiichi; Yasue, Kenichi; Tanaka, Takenobu*; Tsukui, Rota; Matsuo, Koichi*; Sugiyama, Kazutoshi*; Matsuo, Shigeaki*
Chishitsugaku Zasshi, 112(5), p.301 - 314, 2006/05
Fault zones have significant influences on ground water flow. It is important to understand the characteristics of fault zones for hydrogeological modeling. We investigated the hydrogeological property and the geological structure of the fault in Neogene siliceous sedimentary rocks of northern Hokkaido, using geological mappings, reflection seismic surveys, and audio-frequency magneto telluric surveys. The result of description at a fault outcrop suggests that the Omagari Fault is a fault zone of about 120 m width that consists of mainly damage zone and that is a permeable structure without the strong anisotropy in permeability. In addition, the result of magneto telluric surveys shows high-resistivity zones having a flower structure, and one of the high-resistivity zones corresponds to the position of the Omagari fault inferred from the results of the reflection seismic surveys and of the borehole investigations. These high resistivity zones overlap with the low saline concentration zones, and the overlapping suggests the infiltration of the fresh water from the surface into the deeper part through the Omagari Fault as permeable structures. Based on these results and on study of the hydrogeological property, the geological structure, and petrological characteristics in and around the fault, it seems that the fault is a sinistral oblique-slip fault with eastside uplift sense that is formed after late Pliocene to early Pleistocene, but the possibility of the previous activity needs to research, and that the fault is over-stepping at the surface and is converging in deep underground like a flower structure shape.
*; *; Morooka, Koichi*
JNC TJ8400 2000-043, 170 Pages, 2000/03
JNC-TJ8400-2000-043.pdf:7.63MB
This study is an object to collect and arrange data about the mass transfer path during a natural barrier system by grasping actual rock feature, in order to be useful for a performance assessment of a natural barrier system at geological disposal of HLW. An existence of permeability high large-scale faults extends a large influence over a performance assessment of geological disposal. With "The Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan" which Nuclear Cycle Development Institute (JNC) issued, it is as" A repository would be located at least 100 meters away from major faults and major fracture zones which could adversely affect the stability and performance of the repository" as a Reference Case concept model of a natural barrier system, Then, they are as "in the Reference Case, the transport path consists of the host rock and the downstream fault". It will not be easy to know the distribution of faults in the subsurface deep division without data acquired from many boreholes and underground laboratory. With this study, specific data on the large-scale faults and fracture zones has been collected and arranged by investigating in underground galleries and on the literatures of a post-operated mine site. Based on this result, a consideration on the principal transfer pass at a natural barrier system has been conducted. The contents conducted in this report is the follows. (1)investigation of literature about data of fracture, shear zone, and geology, (2)field investigation of fracture and shear zone in the rock, (3)arrangement of these results, (4)modeling of the major water conductive feature, and (5)evaluation of an assumption which has been introduced in the Second Progress Report issued by JNC.
Sasamoto, Hiroshi; Sazarashi, Masami; Ishii, Tomoko*; Kato, Hiroyasu*; Sugiyama, Kazutoshi*
no journal, ,
Regarding to alteration of bentonite coexisting with iron material, laboratory experiments with different temperature and iron-bentonite (I/B) ratio and literature surveys for bentonite alteration in the natural system were conducted. As the results, the conditions which promote the alteration of smectite significantly were estimated approximately. Additionally, the important alteration products necessary for evaluation of smectite alteration were summarized by literature surveys. Such information will be useful for evaluation of smectite alteration considering the conditions of time and duration interested.
