Performance of single piles subjected to vertical and lateral loads in sand

Pile foundations are extensively used in current geotechnical engineering practice to support vertical and lateral loading. However, there is a limited number of experimental studies on the performance of piles under combined loading available in the literature and their results appear to be inconsistent. This study is focused on the experimental investigation of the effects of vertical loading on the lateral resistance of single piles installed in cohesionless soil. To this aim, a series of centrifuge tests were undertaken on single model piles embedded in sand and subjected to pure lateral loads and combined vertical and lateral loads. The tests were conducted at an enhanced acceleration level of 50 gravities in a balanced beam geotechnical centrifuge in medium to dense uniformly graded dry sand. The results are presented through load versus displacement plots, from which lateral capacities are derived for various vertical loads. The test results demonstrate that the pile lateral capacity and stiffness increase when vertical loads are applied, although this beneficial effect on the pile’s lateral response diminishes at values of vertical load equal or greater than the pile’s vertical load capacity and at large displacements.