Quasistatic propagation of compaction fronts in porous rock

Abstract

Recent experimental studies have observed the quasistatic propagation through rock of planar porosity discontinuities. In this process, one or more, initially thin, compacted layers appear at the yield point of the stress–strain curve and then grow by thickening in the direction of maximum compression at constant stress. Strain localization theory was previously applied to compaction to explain the initial formation of the compacted zones. This paper describes the growth of the compaction zones, that is, the propagation of their boundaries, in terms of shock wave analysis. The ratio of the applied shortening rate to the velocity of the boundary is related to the porosity change across the boundary. A small but consistent peak at the yield point of the stress–strain curve is explained by the model.