Laboratory investigation of shaft resistance of rock-socketed piers using the constant normal stiffness direct shear test

Abstract

This paper presents the results of a laboratory investigation of shaft resistance of rock-socketed piers using constant normal stiffness (CNS) direct shear tests. In this context, an experimental program is conducted in which small-scale piers are loaded in compression, and specimens having the same pier-surrounding medium interface geometry and components as those found in the small-scale models are subjected to direct shearing. Pseudorock materials were used for the construction of the model piers and shear specimens. These materials were chosen to simulate rocks of very weak to medium strength to investigate the influence of relative stiffness of pier and surrounding medium construction materials on the shear resistance. Furthermore, predicted values of side shear resistance using empirical relationships are compared with experimental results to examine the validity of these relationships. Key words : rock, socketed piers, shaft resistance, direct shear, model pier, constant normal stiffness.