... are a stationary borehole-gauge and an air-micrometer developed by author. To measure the variation of stresses, over-cored boreholes were used to measure the deformations of the hole. Stress-variation measuring instrument is a kind of borehole deformation meter developed by author. Young's modulus of the over...

... and a borehole gauge designed by author were used. The known applied stresses were compared with the stresses calculated from the theoretical deformation-stress relation on a hole in an elastic and isotropic plate. The results of them were in good agreement. As a result of this study, we learned...