GENERAL-THEORY OF THE KAISER EFFECT

A theory for the generalized Kaiser effect is discussed. Using the concept of a damage surface, the one-dimensional Kaiser effect is extended to a general stress state. Comparisons between the theory and experimental data show agreement in the predicted and observed properties of the Kaiser effect. Implications for the use of the Kaiser effect to determine in situ stress are discussed. It is shown that the commonly-used uniaxial loading method for determining in situ stress is not in accord with theory or observations of the Kaiser effect induced by laboratory-applied stress. An alternative theory of the Kaiser effect observed in cores loaded in situ is proposed.