Shearing of rock joints is a critical failure mode in rock masses. The shear strength of rock joints must, therefore, be considered in the design of structures in rock masses. Several criteria for prediction of shear strength have been proposed over the years. However, the possible effect of scale on shear strength is an issue. One possible reason for this is that previous experimental studies on the scale effect contain vario...

Applying accurate normal load to a specimen in direct shear tests under constant normal stiffness (CNS) is of importance for the quality of the resulting data, which in turn influences the conclusions. However, deficiencies in the test system give rise to a normal stiffness, here designated as system normal stiffness, which results in deviations between the intended and actual applied normal loads. Aiming to reduce these devia...