Onset of Deformation Bands in an Ellipsoidal Reservoir

摘要

The loss of ellipticity of the governing equations is the criteria used to determine the emergence of localization bands, i.e. when the characteristic surfaces of the governing equations become real. This is equivalent to the traditional Rice-Rudnicki approach. However, it becomes essential for the investigation of the post bifurcation behavior of deformation bands. To determine the orientation of the bands Rice-Rudnicki theory requires a minimization of the hardening. In the current paper this condition is not used. An important result of the study is that preconsolidation of the reservoir must be present and is crucial to the appearance of deformation bands. Within the framework of a classical Modified Cam-Clay model the thickness of the bands cannot be calculated. The spacing of the resulting bands will be discussed in a further publication.