Shear zone refraction and deflection in layered granular materials

TL;DR

This study demonstrates that shear zones in layered granular materials refract and deflect similarly to light, obeying Snell's law, which influences deformation patterns under natural pressure conditions.

Contribution

It provides experimental and numerical evidence that shear zones refract according to Snell's law and can be deflected by interfaces under gravity, confirming recent theoretical predictions.

Findings

Shear zones refract in layered systems following Snell's law.

Shear zones can be deflected by interfaces to avoid deformation.

Refraction and deflection observed experimentally and numerically.

Abstract

Refraction and deflection of shear zones in layered granular materials was studied experimentally and numerically. We show, that (i) according to a recent theoretical prediction [T. Unger, Phys. Rev. Lett. 98, 018301 (2007)] shear zones refract in layered systems in analogy with light refraction, (ii) zone refraction obeys Snell's law known from geometric optics and (iii) under natural pressure conditions (i.e. in the presence of gravity) the zone can also be deflected by the interface so that the deformation of the high friction material is avoided.