Journal of The School of Marine Science and Technology,Vol.1 No.1
An experimental study on the validity of Kaiser effect for in-situ stress measurements by Acoustic Emission Method (AEM)
in rocks subjected to cyclic loads
Mitsuo DAIDO, Omer AYDAN, Hitomi KUWAE and Shigemi SAKODA
Abstract
The acoustic emission method utilizes the Kaiser effect for inferring the stress state. Since stress tensor has 6
independent components, uniaxial or triaxial tests in 6 different directions are carried out to infer the components of the
in-situ stress tensor. The acoustic emission response differs when the (deviatoric)stress level exceeds the one at which
material was previously subjected to. The fundamental complexity is that the earth’s crust has a stress history. As a result,
one may find one or several stress levels during actual experiments. The question is how to select or define the one,which
reflects the stress level that rock was subjected to. An experimental study on the acoustic emission responses of initially
unstressed rock-like materials under uniaxial cyclic loading conditions was performed. On the basis of these experimental
results, the validity of Kaiser effect for inferring stress state by considering the stress level with respect to its uniaxial
compressive strength is checked and the applicability of the method for inferring the crustal stresses is discussed.