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Inagaki, Daisuke*; Tsusaka, Kimikazu*; Aoyagi, Kazuhei; Nago, Makito*; Ijiri, Yuji*; Shigehiro, Michiko*
Proceedings of ITA-AITES World Tunnel Congress 2015 (WTC 2015)/41st General Assembly, 10 Pages, 2015/05
Kato, Nobuyoshi*; Tsusaka, Kimikazu; Nago, Makito*; Yamagami, Masahito*; Matsubara, Makoto*; Shigehiro, Michiko*; Aizawa, Takao*; Kamemura, Katsumi*
Chishitsu To Chosa, (139), p.17 - 22, 2014/04
no abstracts in English
Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Aoki, Tomoyuki*; Shigehiro, Michiko*
Proceedings of 6th International Symposium on In-situ Rock Stress (RS 2013) (CD-ROM), p.339 - 346, 2013/08
The Horonobe Underground Research Laboratory is planned to consist of the Ventilation Shaft (4.5 m in diameter), the East and West Access Shafts (6.5 m in diameter). The host rock of the URL site comprises Neogene sedimentary rocks. The unconfined compressive strength of the rocks is less than 20 MPa on average. Anisotropic stress distribution around the URL is also confirmed. Because several highly permeable fractures (hydraulic transmissivity: approximately 10
m
/s) with the size greater than the shaft diameter develop under the condition of around 2 in competence factor (i.e., the ratio of the unconfined compressive strength of rock to the initial stress) below a depth of 250 m, shaft sinking is a challenging issue from the viewpoint of tunnel engineering in the Horonobe URL Project. In this paper, the construction of the Ventilation Shaft below a depth of 250 m at the Horonobe URL is reported. During shaft sinking, fracture mapping of the shaft wall was performed. The geometry of the shaft wall was also measured using a three-dimensional laser scanner in order to investigate the shape and volume of rock spalling in the shaft wall resulting from the excavation work. Rock spalling was predominantly observed on the south and north wall rock corresponding to the direction of the minimum horizontal initial stress. A large amount of rock spalling also developed along a large-scale fault. With respect to the lining span and the layout of rockbolts, several support patterns were designed and installed as the countermeasures to prevent the development of excessive rock spalling. A flowchart for selecting the optimum support design was then developed.
Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Kamemura, Katsumi*; Matsubara, Makoto*; Shigehiro, Michiko*
Proceedings of ITA-AITES World Tunnel Congress 2013 (WTC 2013)/39th General Assembly, p.2014 - 2021, 2013/05
Japan Atomic Energy Agency (JAEA) has been constructing three shafts to a depth of 500 m in the Horonobe Underground Research Laboratory Project. In this study, in consideration of support patterns installed, a relationship between the rock mass properties and mechanical response to excavation was investigated in detail during the construction of the East Access Shaft below a depth of 250 m. Since the shaft has intersected several faults with the size greater than the shaft diameter, some amounts of rock spalling have occurred and cracks have severely developed in a concrete lining in highly fractured zones. The results of pre-excavation grouting were compared with the results of fracture mapping in the shaft wall obtained during the shaft sinking. Applicability of several support patterns installed to control massive spalling during the shaft sinking was also analysed using the results of geometry profiling of shaft wall using a three-dimensional laser scanner and convergence measurements. As a result, based the empirical relationships among the characteristics of rocks, dimension of spalling, damage of a concrete lining and support patterns, a flow chart for selection of span of a concrete lining was proposed to control its severe damage prior to shaft excavation.
Tsusaka, Kimikazu; Inagaki, Daisuke; Tokiwa, Tetsuya; Yokota, Hideharu; Nago, Makito*; Matsubara, Makoto*; Shigehiro, Michiko*
Proceedings of ITA-AITES World Tunnel Congress 2012 (WTC 2012)/38th General Assembly (CD-ROM), 8 Pages, 2012/05
In the Horonobe URL Project, three shafts are planned to be excavated up to the depth of 500 m in the Neogene sedimentary rocks. The host rock of the URL site is comprised of diatomaceous and siliceous mudstones, which are the Koetoi and Wakkanai Formations, respectively. Approximately 100 m thick fracture zone with high hydraulic conductivity develops above about 400 m in depth in the Wakkanai Formation. The shaft sinking through the fracture zone is the most challenging issue from the aspect of tunnel engineering in the project. In the fracture zone, there is high possibility of severe breakout and spalling in shaft wall because the shafts might be intersecting faults with the size greater than shaft diameter in addition to low intact rock strength at great depth. In practice, prior to the construction of the Ventilation Shaft through the fracture zone below a depth of 250 m, the three dimensional fault distribution were predicted by integrating borehole investigation results and geological response to pre-excavation grouting operation. The countermeasure was also designed against massive spalling. During the shaft sinking, fracture mapping of shaft wall was carried out in order to evaluate the prediction of fault distribution. Roughness of shaft wall was also measured by three dimensional laser scanner in order to investigate the shape and volume of spalling resulting from the excavation work. Consequently, the Ventilation Shaft has successfully been constructed through the fracture zone. This is because the prediction of fault distribution was accurate, and the countermeasure against concrete lining damage due to spalling was promptly applied.
Nakayasu, Akio; Niizato, Tadafumi; Yasue, Kenichi; Doke, Ryosuke; Shigehiro, Michiko*; Tanaka, Takenobu*; Aoki, Michinori*; Sekiya, Ayako*
JAEA-Research 2010-056, 116 Pages, 2011/02
JAEA-Research-2010-056.pdf:28.28MB
The investigation methods for characterizing natural events and processes in a coastal field have been extracted on the basis of analysis of previous research. Collected information is classified into three groups according to characteristics of natural events/processes and investigation methods. First group is the methods for evaluation of uplift, subsidence and sedimentation rates. Second group is the methods for evaluation ob denudation rates. The third group is the methods for reconstruction of the climatic and sea-level changes. Based on an analysis of the above information, investigation method that can be applied to a coastal region was extracted. The methods and indices are as follows: (1) Uplift rate: the heights of marine terraces are the most important index in an upheaval region. (2) Subsidence and sedimentation rate: the depths of strata underlying an alluvial plain are main indices in a subsidence region. (3) Denudation rate: the features of marine terrace are main indices and the inspection of denudation processes by the use of a numerical simulation is necessary. (4) Climate change: lacustrine deposits are main object for investigation. (5) Sea-level change: reconstruction of relative sea-level change curve including uplift/subsidence factor and paleography based on acoustic exploration and the investigation of marine terraces.
Osawa, Hideaki; Ota, Kunio; Hama, Katsuhiro; Sawada, Atsushi; Takeuchi, Shinji; Amano, Kenji; Saegusa, Hiromitsu; Matsuoka, Toshiyuki; Miyamoto, Tetsuo; Toyoda, Gakuji; et al.
JAEA-Research 2008-085, 742 Pages, 2008/11
JAEA-Research-2008-085-1.pdf:26.22MBJAEA-Research-2008-085-2.pdf:16.64MBJAEA-Research-2008-085-3.pdf:28.27MB
This report shows the results the project for the establishment of comprehensive site characterization technology, entrusted from Natural Resources and Energy Agency, Ministry of Economy, Trade and Industry Natural Resources and Energy Agency in 2007.
Nago, Makito*; Ijiri, Yuji*; Kinomura, Koji*; Sato, Masaru*; Shigehiro, Michiko*; Kunimaru, Takanori
no journal, ,
Since a geological disposal repository of nuclear waste will be constructed at depth of a few square kilometers and will be operated for a several tens years, it is crusial to develop a long-term monitoring technology of rock behavior of quite large area. For this purpose, a conventional monitoring method needs a number of deep boreholes and thus needs a huge amount of cost. In this paper, the results of tilt measurements for the shaft excavation at the Horonobe Underground Research Laboratory is presented.
Ijiri, Yuji*; Nago, Makito*; Kinomura, Koji*; Sugihara, Yutaka*; Shigehiro, Michiko*; Sato, Masaru*; Kunimaru, Takanori
no journal, ,
This paper presents the in-situ measurement data and the results of simulation analyses in order to develop technologies for monitoring rock behaviors using tiltmeters placed near ground surface. From the data, it is shown that the tiltmeters are able to capture the rock behaviors due to shaft excavations and concrete placements and are very sensitive to capture earthquakes, change in barometrical pressure and tide as well as the movements of heavy-construction-equipments. The applicability of inverse analysis for identifying the rock properties using tilting displacement data associated with construction activity is demonstrated by elastic analyses. In addition, the applicability of tiltmeters for monitoring high-permeable zones is also demonstrated by Hydro-Mechanical coupling analysis, because the groundwater flow toward the shaft along high-permeable zone cause an increase in the rate of tilting displacement and change in displacement mode.
Shigehiro, Michiko; Toyoda, Gakuji; Osawa, Hideaki; Miyamoto, Tetsuo; Sato, Masaru*
no journal, ,
no abstracts in English
Niizato, Tadafumi; Yasue, Kenichi; Nakayasu, Akio; Shigehiro, Michiko*
no journal, ,
no abstracts in English
Nakayasu, Akio; Yasue, Kenichi; Niizato, Tadafumi; Doke, Ryosuke; Shigehiro, Michiko*
no journal, ,
no abstracts in English
Niizato, Tadafumi; Yasue, Kenichi; Doke, Ryosuke; Nakayasu, Akio; Shigehiro, Michiko*
no journal, ,
no abstracts in English
Shirase, Mitsuyasu*; Nago, Makito*; Nakayama, Masashi; Ono, Hirokazu; Sanoki, Satoru*; Shigehiro, Michiko*
no journal, ,
Full-scale engineered barrier system (EBS) experiment for high-level waste disposal is being conducted by the Japan Atomic Energy Agency at 350m level gallery in Horonobe Underground Research Laboratory, Japan, in order to obtain data for evaluating coupled THMC phenomena overtime after the installation of the EBS. This paper presents planning construction and monitoring of the engineered barrier system experiment by Construction Information Modeling.
