Predicting Uplift Behaviour of Anchor Pile in Loose Sandy Soil: A Numerical Analysis

Loose sandy soil poses foundation challenges due to weak compaction and cohesion, leading to settlement risks and structural instability. The earlier used techniques (vibroflotation, pile compaction, dynamic compaction) carried out to mitigate these issues are costly, time-consuming and impractical for small-scale construction projects. The current study aims to evaluate anchor pile behaviour in loose sandy soil by varying pile parameters and soil conditions using finite element-based software PLAXIS 3D. The soil was tested in saturated and unsaturated conditions. The uplift force was measured at the top of the base plate, where a prescribed displacement of 10% of the pile diameter was applied. The numerical studies revealed an increment in anchor pile's uplift capacity on increasing its length (L) and diameter (D). Ultimately, the analysis revealed that an anchor pile system installed in unsaturated soil had an approximately 46% higher uplift capacity than the system installed in completely saturated soil. The uplift force in the pile group (for varying spacing) was found to be increased with increase in number of piles and the efficiency of pile group was decreased on increasing number of piles. The efficiency of the anchor pile system was slightly varied when the spacing was increased from 3D to 3.5D, indicating that 3D may be chosen as the optimum spacing value for group anchor pile systems. By preventing foundation failures, this anchor pile system's structure is able to withstand the uplift forces developed under loose, sandy soil, leading to a stable foundation system.