Overcoring stress measurement considering anisotropy at a Neogene sedimentary rock in Japan

One of the major overcoring techniques widely used in Japan has adopted a new procedure of determining orthotropic anisotropy by a pressure cell test of a retrieved over-core. A procedure of stress analysis considering the anisotropy of rock has also been devised. This new method of rock stress measurement has been applied to a soft sedimentary Neogene rock in Japan. This paper describes the outline of the development and the result of the application.