Mesomechanics of shear resistance along a filled crack

Abstract

The paper reports on laboratory experiments with the aim of studying the effect of microstructural and macromechanical properties of a crack filled with discrete material on the formation of a sliding mode. It is shown that the spectrum of possible deformation events on the discontinuity is governed by both the macroscopic characteristics of the gouge and its mesoscale structure. The evolution of force bridges which are formed and collapsed in shear along the crack, their length and number fully control the type of deformation—stable sliding, stick-slip, and intermediate modes with low-velocity motion of the crack edges. The variation of the Coulomb strength affects mainly the stress drop value in dynamic failure or a slip event with low displacement velocity and little affects the deformation mode. Consideration is also given to the regularities by which the macroscopic characteristics of contact vary in shear.