Lacunarity of contact domains and multifractality of pressures in rough rock interfaces

Abstract EN

The correct evaluation of the shear behavior of rock joints is of fundamental importance in slope stability analysis.

A strong size-dependence of shear strength has been detected.

The study of the force exchange mechanism at the joint interface, supported by the proper description of the fractal contact domain, represents the mean to provide a size-independent definition of the frictional parameters.

In this work, the topography of a real fracture surface in a rock sample has been digitized by means of a laser apparatus.

The behavior of the rock joint under normal loading has been studied, by means of a numerical model, for different shear displacements of the initially matching surfaces.

The crack closure laws and the dilatancy curves relating shear displacement to normal opening of the interfaces, have been analyzed.

The lacunar fractality of the true contact domains is evidenced and the distributions of micro-forces at the interface are shown to possess multifractal characteristics.