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Journal Articles

Diagrams for finite strain equations and rough estimation of shear strain

Shimada, Koji

Chishitsu Gijutsu, (9), p.25 - 40, 2019/09

Today many collaborations are there in Earth-scientific research and development. Structural geology can serve crucial information on tectonic strain at sampling point in Japan, belonging to the circum-Pacific orogenic belt. Visualize of strain estimation would be effective during field geological survey and for better understanding for non-specialist on structural geology. Illustrations decoding mathematical expressions of strain estimation methods are presented here.

Journal Articles

Geological mapping on the shafts and galleries walls on the Mizunami Underground Research Laboratory project

Tsuruta, Tadahiko; Sasao, Eiji

Oyo Chishitsu, 56(6), p.298 - 307, 2016/02

https://doi.org/10.5110/jjseg.56.298

Japan Atomic Agency (JAEA) are performing Mizunami Underground Research Laboratory project (MIU project), which is a broad scientific study of the deep geological environment as a basis of research and development for geological disposal of nuclear wastes. Geological investigations, reflection seismic surveys, borehole drilling, etc., are carried out to understand the distribution and properties of important geological structures (permeable fractures, faults, etc). This report summarizes specifications and data characteristic of geological mapping on the shafts and gallery wall, and describes contributions to developments of geological model based on the results of geological mapping.

JAEA Reports

The Arrangement of the seismic design method of the underground facility

Tanai, Kenji; Horita, M.*; Dewa, Katsuyuki*; Goke, Mitsuo*

JNC TN8410 2001-026, 116 Pages, 2002/03

JNC-TN8410-2001-026.pdf:9.19MB

Earthquake resistance for the underground structure is higher than the ground structure. Therefore, the case of examining the earthquake resistance of underground structure was little. However, it carries out the research on the aseismic designing method of underground structure, since the tunnel was struck by Hyogo-ken Nanbu Earthquake, and it has obtained a much knowledge. However, an object of the most study was behavior at earthquake of the comparatively shallow underground structure in the alluvial plain board, and it not carry out the examination on behavior at earthquake of underground structure in the deep rock mass. In the meantime, underground disposal facility of the high level radioactive waste constructs in the deep underground, and it carries out the operation in these tunnels. In addition, it has made almost the general process of including from the construction start to the backfilling to be about 60 years (Japan Nuclear Fuel Cycle Development Institute, 1999). During these periods, it is necessary to also consider the earthquake resistance as underground structure from the viewpoint of the safety of facilities. Then, it extracted future problem as one of the improvement of the basis information for the decision of the safety standard and guideline of the country on earthquake-resistant design of the underground disposal facility, while it carried out investigation and arrangement of earthquake-resistant design cases, guidelines and analysis method on existing underground structure, etc.. And, the research item for the earthquake resistance assessment of underground structure as case study of the underground research laboratory.

JAEA Reports

Long-term immersion tests of engineered materials in the Tono mine; Results for glass material

Hama, Katsuhiro; Mitsui, Seiichiro; Aoki, Rieko*; Hirose, Ikuro

JNC TN7430 2000-001, 47 Pages, 2000/12

JNC-TN7430-2000-001.pdf:4.09MB

Long-term immersion tests of glass material at ambient temperature (about 18 $^{circ}$ C) for 10 years were performed in a gallery at the Tono mine in Japan, in order to assess durability of glass matelial contacted with natural groundwater. The gallery was constructed at a depth of 130 m below ground surface in the Toki Granite. Monolithic glass blocks with dimensions of 10 10 10 mm (cubic type) and of 25 mm in diameter and 8 mm in thickness (disk type: The wall of sample was covered by stainless steel of 1 mm thick.) were used for the tests. Both type of samples with and without clay were put in Teflon vessels, which have small holes on the wall, and inserted into boreholes excavated at the gallery floor. In addition to the immersion tests, static leaching test with cubic type glass and ground water was also performed at the gallery. The samples of each test were collected in time intervals of 6 months, 1 year, 2 years, 3 years and 10 years and were subjected to weight loss measurement and several surface analyses. The results were as follows: (1)Weight losses of each sample were proportional to time intervals. This result is attributable to constant dissolved silica concentration in the ground water during tests. (2)The weight losses of disk type glass were slightly larger than those of cubic type glass. This result is attributable to elemental release from internal cracks of disk type glass, instead of effect of stainless steel on the glass dissolution. (3)The weight losses for the tests with clay were slightly smaller than those for tests without clay. This result is attributable to higher concentration of dissolved silica in pore water of clay.