Socket roughness effect on side shear resistance prediction of rock-socketed piles

Abstract

Rock-socketed piles have been extensively employed to receive and transmit large concentrated loads to deeper stronger materials. Although the load transfer mechanism combines base and side resistances, the contribution of side shear resistance is often crucial, as it is usually mobilized at much lower strains (or pile settlements) than base resistance. The side shear resistance of rock-socketed piles has usually been estimated using recommendations from codes and standards, or using local knowledge obtained from full-scale static load tests performed in similar ground. There are also empirical formulations as a function of the uniaxial compressive strength of the intact rock. However, this approach neglects the influence of other important aspects such as the effect of roughness at the rock-pile interface, and this factor is not always being considered in current design practices. The aim of this work is to examine the socket roughness effect on side shear resistance of rock-socketed piles. To do that, DEM2D numerical models of direct shear tests, and DEM3D numerical models of rock-socketed piles with different degrees of socket roughness are employed. Numerical results suggest that socket roughness is an important factor that significantly increases the load capacity and stiffness of rock-socketed piles.