Study on core disking phenomenon on compact conical-ended borehole overcoring technique

Sato, Toshinori; Tanno, Takeo; Hikima, Ryoichi; Sanada, Hiroyuki; Kato, Harumi*

Heisei-24 Nendo (2012 Nen) Shigen, Sozai Gakkai Shuki Taikai Koenshu, p.221 - 222, 2012/09

Japan Atomic Energy Agency has been conducting stress measurements by overcoring method, to aiming establish a firm scientific basis for safe geological disposal. Core disking is observed where rock stress measurements are performed by compact conical-ended borehole overcoring technique in the depth of 300m from the surface at the Mizunami Underground Research Laboratory. In this report, failure initiation of core disking is discussed.