Sensitivity Assessment and 3D Finite Element Analysis of the Behavior of Bored Capped Pile in Sandy Soils Under Axial Tensile and Lateral Loading

This study employs variance-based and parametric analyses to quantify the impact of geometric and mechanical properties on the performance of pile foundations under axial tensile (P a ) and lateral (P L ) loading. Utilizing 3D finite element analysis with the Drucker-Prager model, the research investigates pile-pile cap interaction across varying soil moduli (E s = 5, 20, & 50 MPa) and length-to-diameter (L/D) ratios (10, 20, & 33). The sensitivity analysis identifies the friction coefficient between sand and pile, as well as pile diameter, as the most influential factors, followed by pile length and the Young’s modulus of both the pile and the sand. Parametric analysis reveals that pile deformation, contact pressure (P c ), and shear stresses (f s ) are strongly affected by Es and the L/D ratio. Under Pa loading, as Es and L/D decrease, fs increases up to a certain depth before decreasing. Additionally, the normalized Pa to axial deformation ratio (P a /δ a ) decreases with increasing relative stiffness of the pile to soil (E p /E s ), with L/D becoming increasingly influential as E p /E s decreases. Under P L loading, increased L/D and E s result in greater pile flexibility and a concentration of P c at the top. The pile’s lateral deformation behavior with depth mirrors the P c distribution.