Distinct-Element Method Simulations of Rock-Socketed Piles: Estimation of Side Shear Resistance Considering Socket Roughness

Abstract

Rock-socketed piles are foundational elements designed to transmit large concentrated loads to stronger materials located at greater depths. The rock-socket side shear resistance is commonly estimated using empirical criteria as a percentage of the rock or concrete uniaxial compressive strength. However, this approach neglects the influence of other important aspects, such as the roughness of the pile-socket interface. In this work, numerical discrete-element models of rock-socketed piles with different degrees of socket roughness are employed to estimate the influence of the socket roughness on the load-settlement response and on the side shear resistance. The numerical simulation results are compared with predictions obtained using empirical correlations based on load test results and proposed by other authors. Results indicate that the discrete-element method is suitable to reproduce rock-socket pile behavior considering socket roughness; they also suggest that sockets drilled with standard tools in soft to medium rock tend to be relatively smooth unless artificially roughened with special tools and that damage to the interface asperities becomes more relevant after socket settlement of about 1% of the socket diameter, especially for rougher piles.