The influence of soil reinforcement on the uplift behaviour of belied piles embedded in sand

The influence of soil reinforcement on the uplift performance of belied piles or piers of various geometries embedded in sand at various densities is investigated in tests at unit gravity. Several configurations of geogrid reinforcement are compared and a cylindrical gravel-filed geogrid cell located around the enlarged pile base is found to provide the most beneficial overall effect. Pullout resistance increases with the diameter of the geogrid cell, sand density, pile bell diameter and embedment. Moreover the enhanced resistance is stable even for large displacements, indicating a ductile response, differing markedly from that of belied piles in unreinforced sand where a pronounced reduction in post-peak resistance is observed. (C) 2001 Elsevier Science Ltd. All rights reserved.