DEM Models to Predict Side Shear Resistance of Rock-Socketed Piles Considering Socket Roughness

Abstract

Rock-socketed piles are designed to receive and transmit large concentrated loads to deeper stronger materials. Although the load transfer mechanism combines base and side resistances, the side shear resistance is usually mobilized at much lower strains 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 load tests performed in similar ground. There are also empirical formulations as a function of the uniaxial compressive strength of the intact rock (UCS). However, this approach neglects the influence of other important aspects such as the roughness at the pile-rock interface. This work examines the socket roughness effect on side shear resistance of rock-socketed piles, using DEM3D numerical models of rock-socketed piles with different degrees of socket roughness. Numerical results suggest that socket roughness is an important factor that significantly increases the load capacity and stiffness of rock-socketed piles. Finally, a new approach to predict preliminary the average side shear resistance of rock-sockets is analysed, considering the socket roughness and the UCS of the intact weaker material (rock or pile).