Effect of combined lateral and uplift loads on vertical and batter pile groups in cohesion less soil

Batter pile foundation is known for sustaining high lateral loads but due to wind, waves, or both, overturning moments are applied on the pile foundation which leads to lateral as well as uplift movements of the pile groups. Batter piles used in the pile groups will lead to a safer structure in case of floods or large lateral loads acts. However, a suitable angle at which a batter pile should be driven is important. Therefore, a model study was conducted to understand the behavior of the vertical and batter pile groups under combined lateral and uplift loads. The effect of change in batter angle of the pile and L/D ratio is also observed in the study. Model piles and model tank were made up of mild steel. The piles had different lengths 396 mm, 616 mm and 836 mm and an outer diameter of 22 mm. Physical modeling of the pile group was done to eliminate the boundary condition effects. Different loads were applied on vertical and batter pile groups in a testing tank having sand as a foundation bed. Piles groups having different batter angles 15°, 25°, 35° and 45° were used in the study. It was observed that the pile groups when subjected to combined loads provides substantially higher load capacity than under monotonic lateral or uplift loads. It is found that the negative batter pile group having 35° angle provides maximum load capacity in every load condition. It is also observed that the length to diameter ratio of the pile group also have a considerable effect on the load capacity of the pile.