Measurement of secondary stress around excavation by the stress release method

Itamoto, Masaharu*; Tanaka, Masahiro*; Tanno, Takeo*

PNC TJ7592 98-001, 166 Pages, 1998/03

PNC-TJ7592-98-001.pdf:8.43MB

None

None

Itamoto, Masaharu*; *; Tanaka, Masahiro*

PNC TJ7592 96-001, 164 Pages, 1996/03

PNC-TJ7592-96-001.pdf:9.73MB

no abstracts in English

Initial stress measurement by CCBO at the Mizunami Underground Research Laboratory GL-500m

Kuwabara, Kazumichi; Takayama, Yusuke; Sanada, Hiroyuki; Sato, Toshinori; Tanno, Takeo*; Itamoto, Masaharu*; Kato, Harumi*

no journal, , 

In-situ stress measurements using CCBO (Compact Conical-ended Borehole Overcoring technique) were performem with two boreholes (13MI34, 13MI35) at depth of 500m in Mizunami Underground Research Laboratory. As a results, the Maximum stress in the horizontal plane was 15 MPa, and its azimuth were nearly N-S direction.

Initial stress measurement by CCBO at GL.-500m closure test drift of the Mizunami Underground Research Laboratory

Kuwabara, Kazumichi; Sato, Toshinori; Takayama, Yusuke; Tanno, Takeo*; Kato, Harumi*; Itamoto, Masaharu*

no journal, , 

It is very important to understand an initial stress state of the rock mass in doing a design, the construction of large-scale facilities under the ground. Groundwater recovery experiment will be conducted at the MIU GL.-500m closure test drift. This report described what stress measurement were performed by the CCBO (Compact Conical-ended Borehole Overcoring technique) to understand an initial stress state of intact rock and a stress state of the -500m gallery wall surface. As a result, the magnitude of principal stresses were 16.8 MPa, 10.2 MPa and 7.5 MPa. The maximum principal stress level was approximately same at the GL.-500m level. The direction of maximum principal stress is approximately 60 from a horizontal plane. The width of stress redistributed zone was about 2m from the wall of research galleries. Numerical analysis was carried out to examine an outbreak condition of core disking.