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Yamanoi, Tadayo*; *; *; Odagawa, Shinya*

PNC TJ7361 97-006, 121 Pages, 1997/08

PNC-TJ7361-97-006.pdf:5.33MB

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None

PNC TJ1380 95-001, 82 Pages, 1995/05

PNC-TJ1380-95-001.pdf:3.48MB

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*; *; *

PNC TJ1677 95-001, 222 Pages, 1995/03

PNC-TJ1677-95-001.pdf:7.53MB

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None

*

PNC TJ7586 95-004, 102 Pages, 1995/02

PNC-TJ7586-95-004.pdf:2.99MB

no abstracts in English

A Study on fractures in the crystalline rock; Analysis of properties and distribution of fractures in the granitic rock

Yoshida, Hidekazu; Osawa, Hideaki

PNC TN7410 90-007, 31 Pages, 1991/03

PNC-TN7410-90-007.pdf:1.44MB

For performance assessment of the geological disposal system, it is essential to evaluate groundwater flow in rock formations. Rock mass heterogeneity, which is considered to be derived from properties and distribution of fractures, might be taken as an important factor of groundwater flow analysis. In order to comprehensively assess the fracture characteritics, fractures were classified basically according to the geometrical properties such as fracture pattern, roughness of fracture surface and angle of fracture including mineralogical analysis of fracture fillings, using the core samples obtained by drilling in the granitic rock in Tono area. On the basis of this classification, the rock mass was divided in to formational segments from the surface to 500 meter below ground level. The results are as follows; (1)Based on the difference of fracture pattern, the fractures of crystalline rock can be classified into four groups; i.e. Planar fracture (P) group, Irregular fracture (I) group, Curved fracture (C) group and Stepped fracture (S) group. (2)P group with a higher angle has smooth fracture surface with striation. Approximately 70 per cent of this group has such filling minerals as chlorite, sericite and calcite. The fractures of I group, about 20 per cent of which has filling minerals, are characterized by rough surface without striation and with lower angle. C group and S group have curved and stepped surfaces, respectively. (3)In the granitic rock of this area, each groups have difference in their distribution by which three segments are recognized from the surface to 500 meter below ground level; i.e. Segment I (16m to 300m), Segment II (300m to 420m) and Segment III(420m to 500m). (4)Segment I and II are mainly dominated by the fracture of P and S groups, respectively, Segment III is quite low in fracture density.