Influence of discontinuity inclination on the shear strength of mont terri opalinus claystones

Abstract

The shear strength of rocks along discontinuities has the highest influence on rock slope stability; therefore, its accurate determination is crucial. This paper presents a potential solution for the 3D surface detection of the rock discontinuity surfaces by using photogrammetric methods (ShapeMetriX3D), from which one of the most important shear strength influencing parameters can be determined and analyzed. From the determination of the angle enclosed by the plane of the sample surface and the shear plane in the direction of shear, besides the effect of the upslope/downslope shearing further analysis can be carried out in case the examined rock sample contains bedding planes or foliation. The magnitude of the influence on the shear strength for both cases is demonstrated on existing direct shear strength test measurements that were carried out on over-consolidated Mont Terri Opalinus Claystones from the Rock Laboratory of Mont Terri in Switzerland.