Experimental analysis on Rowe's stress-dilatancy relation and frictional instability of fault gouges

Abstract

The stress-dilatancy relation is important for understanding fault mechanics and brittle deformation of rocks, and hence the onset of frictional instability. The principle of minimum energy ratio was proposed by Rowe, and this Rowe's theory has been applied to deformation of granular materials. Rowe suggested that the energy ratio, which is the ratio of the energy dissipation rate to energy supply rate, would be a minimum and constant value. The relation between the rate of dilatancy and the maximum stress ratio can be extended to the case of a random assembly of irregular particles whereby the rate of internal work absorbed in frictional heat is a minimum as the mass dilates. According to Rowe's law, experiments show that the minimum energy criterion is closely obeyed by highly dilatant dense over-consolidated and reloaded assemblies throughout deformation. However, it is unknown whether or not the principle of minimum energy ratio can be applied to fault mechanics. The results of our friction experiments show the possibility that the energy ratio can be a new factor for evaluating frictional instability.