Análisis numérico del efecto de la rugosidad en el contacto pilote-roca sobre la resistencia por fuste y punta

Résumé

The main goal of this research is the study of the effect of shaft roughness on end bearing, and side shear resistance in the design of axially loaded drilled shafts in rock. In order to model that effect, the finite element method (FEM) using a commercial program is developed. The empirical correlations for estimating the end bearing and side shear resistance of drilled shaft in rock are described. The contact surface of the pile shaft drilled in rock is introduced in numerical model in agreement with the proposal by Pells et al. (1980) in Plaxis, and a sinusoidal profile according to O'Neill et al. (1996) in Abaqus. The influence of different roughness classes on complex me-chanisms of load transfer at the interface between the socketed piles and the surrounding rock is shown. Diverse results are obtained by numerical modeling being presented by following relationships: (1) axial load mobilized in pile-depth, (2) side shear resistance mobilized-depth, (3) load-end bearing and side shear resistance relations-hip, (4) load-resistance mobilized, (5) load-settlement. The results are compared to empirical correlations propo-sed by different researchers. As conclusions none of empirical formulations can satisfactorily estimate side shear resistance because they do not consider the “real” roughness effect in shaft-rock interaction. Therefore, the design of drilled shafts in rock is generally overestimated. The results confirm the excessive simplification in considering only side shear or only end bearing resistance in the pile design. There is a mutual dependence between end bea-ring and side shear resistance that should be considered in the analysis of deep foundations.