TY - JOUR
T1 - A new method of diametrical core deformation analysis for in-situ stress measurements
AU - Funato, Akio
AU - Ito, Takatoshi
N1 - Funding Information:
This work was partly supported by a Grant-in-Aid for Scientific Research 21107006 ( Ministry of Education, Culture, Sports, Science and Technology , MEXT), Japan.
Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2017/1/1
Y1 - 2017/1/1
N2 - A new method of diametrical core deformation analysis (DCDA) is proposed for evaluating the in-situ stress of rocks from an elliptical deformation of boring cores following stress relief. When a piece of rock at depth is cut out to be a core sample by drilling, it becomes free from the in-situ stresses resulting in the expansion of its diameter. Even if the rock is homogeneous and isotropic, the core sample should expand in an asymmetric manner with the relief of anisotropic in-situ stresses. A newly developed apparatus allows us to measure the asymmetric variation of the core diameter. The difference between the maximum and minimum stress components and the stress orientations in a plane perpendicular to the drilled hole can then be estimated from the circumferential variation of the measured core diameters based upon a theoretical relationship between the in-situ stresses and the core diameters, assuming elastic deformation. We carried out laboratory experiments in which core samples were cut out from cubic specimens under uniaxial compression, and we confirmed that the stress magnitude and orientation estimated from the measured core diameters by the proposed DCDA method agreed well with those of the actually applied stress.
AB - A new method of diametrical core deformation analysis (DCDA) is proposed for evaluating the in-situ stress of rocks from an elliptical deformation of boring cores following stress relief. When a piece of rock at depth is cut out to be a core sample by drilling, it becomes free from the in-situ stresses resulting in the expansion of its diameter. Even if the rock is homogeneous and isotropic, the core sample should expand in an asymmetric manner with the relief of anisotropic in-situ stresses. A newly developed apparatus allows us to measure the asymmetric variation of the core diameter. The difference between the maximum and minimum stress components and the stress orientations in a plane perpendicular to the drilled hole can then be estimated from the circumferential variation of the measured core diameters based upon a theoretical relationship between the in-situ stresses and the core diameters, assuming elastic deformation. We carried out laboratory experiments in which core samples were cut out from cubic specimens under uniaxial compression, and we confirmed that the stress magnitude and orientation estimated from the measured core diameters by the proposed DCDA method agreed well with those of the actually applied stress.
KW - Core sample
KW - Elastic deformation
KW - In-situ differential stress
KW - Stress relief
UR - http://www.scopus.com/inward/record.url?scp=84998799629&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84998799629&partnerID=8YFLogxK
U2 - 10.1016/j.ijrmms.2016.11.002
DO - 10.1016/j.ijrmms.2016.11.002
M3 - Article
AN - SCOPUS:84998799629
VL - 91
SP - 112
EP - 118
JO - International Journal of Rock Mechanics and Mining Sciences
JF - International Journal of Rock Mechanics and Mining Sciences
SN - 1365-1609
ER -