Influence of Discontinuity Inclination on the Shear Strength of Mont Terri Opalinus Claystones

The shear strength of rocks along discontinuities has the highestinfluence on rock slope stability; therefore, its accuratedetermination is crucial. This paper presents a potential solutionfor the 3D surface detection of the rock discontinuity surfacesby using photogrammetric methods (ShapeMetriX3D),from which one of the most important shear strength influencingparameters can be determined and analyzed. From thedetermination of the angle enclosed by the plane of the samplesurface and the shear plane in the direction of shear, besidesthe effect of the upslope/downslope shearing further analysiscan be carried out in case the examined rock sample containsbedding planes or foliation. The magnitude of the influence onthe shear strength for both cases is demonstrated on existingdirect shear strength test measurements that were carried outon over-consolidated Mont Terri Opalinus Claystones from theRock Laboratory of Mont Terri in Switzerland.