Response of Single Pile to Lateral Load with Constant Uplift

Model tests and the corresponding three dimensional FE analyses using PLAXIS 3D have been carried out to study the behavior of a single pile under combined action of lateral loading and uplift. Cast-iron model piles of 25 mm diameter and slenderness ratios (L/d) of 20, 25, and 30 have been chosen for the study. The variation of ultimate lateral load with pile head deflection with and without different values of uplift load has been obtained to examine the effect of relative density (R.D) of sand, and L/d ratio of pile on the ultimate pile capacity in both homogeneous and layered deposits of sand. Results indicate that the load–deflection behavior is nonlinear for independent lateral and uplift load, as well as in case of combined loading. It has been also found that independent lateral and uplift capacities of piles obtained from numerical analysis agree well with available theoretical and experimental results for the respective cases. Also, under combined action of lateral load and uplift, increase in lateral load capacity has been found to occur with increase in uplift load for a given L/d ratio, both in homogeneous and layered soil. It has also been observed that for any given L/d ratio, the ultimate lateral capacity decreases for a particular uplift in case of layered deposits when the thickness of topsoil layer (of lower R.D) increases.