Influence of Stratified Soil System on Behavior of Laterally Loaded Pile Groups: An Experimental Study

Laterally loaded piles are most commonly used in foundations of structures subjected to wave action, winds, earthquakes and traffic loading. More complexity is involved in analyzing the pile group response under the action of lateral loads. Soil–pile interaction significantly influences the behavior of pile groups under lateral loading. The current study aims to understand the behavior of individual pile and pile groups under lateral loads in uniform sand (relative density 80%) and stratified soil (sand overlain by clay) by conducting laboratory model tests. Test tank of length 1.52 m, width 0.76 m, height 1.2 m and model aluminum test piles of 16 mm diameter (D) and aspect ratios 12, 25 and 40 were used for the tests. The response of individual pile and 2 × 2 pile group was evaluated in terms of deflection at pile head for varying aspect ratio and pile spacing of 3D, 5D and 7D for the case of pile groups. The lateral load taken by the single pile for a deflection of 0.2D in the stratified soil was increased by 200% compared to that of the pile embedded in the uniform sand. It is noted that at all stages of the loading, the pile head deflection of the single pile and pile group was reduced for the stratified soil when compared to the uniform sand bed. However, the efficiency of the pile groups embedded in the stratified soil medium was observed to be less than that of the pile groups embedded in the uniform sand.