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*

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.