A DEM-Based Factor to Design Rock-Socketed Piles Considering Socket Roughness

The Distinct Element Method (DEM) has gained recent attention to study geotechnical designs with rock-concrete or rock–rock interfaces, such as rock-socketed piles. In this work, 3D DEM models with non-standard contacts laws (the Smooth-Joint and Flat-Joint contact models) are proposed to analyze the response of axially loaded rock-socketed piles with different sockets roughness, since socket roughness is a key factor affecting their side shear resistance that is not usually considered for pile design. DEM models are calibrated using experimental data, and the consequences of applying 2D models for calibration, to be subsequently used in a 3D analysis, are studied. Numerical results suggest that such DEM models can be employed to reproduce key aspects of the behavior of rock-socketed piles, such as their load and global stiffness-settlement response, their side shear resistance, and the damage at the rock-pile interface. Finally, an empirical factor \({\alpha }_{RF,1\%D}\) is proposed to estimate the side shear resistance of rock-socketed piles considering the socket roughness and the uniaxial compressive strength (UCS) of the weaker material (rock or pile) at the interface.