Influence of Uncertainty in the Elastic Modulus of Soil on the Combined Axial and Laterally Loaded Pile Group

Pile foundations generally experience various combinations of lateral and vertical load components i.e., axial and lateral loads. The present finite-difference study examines the static response of the pile group subjected to the combined vertical and lateral loads in the cohesionless soil. The soil is considered as a Mohr–Coulomb constitutive material, the pile material as linearly elastic material and the pile cap as a shell element in this study. A 2 × 2 pile group embedded in the cohesionless soil is considered in the study. The behaviour of the pile group relates to the properties of soil medium, especially the fiction angle and the elastic modulus. It is well known that the soil, being the natural material, comprises uncertainties in its parameters. The parameter uncertainty i.e., the variation of the soil property is incorporated with the use of lognormal probability distribution pertaining to the parameter’s coefficient of variation. The elastic modulus of the soil is considered for the inclusion of parameter uncertainty in the present three-dimensional study. The aim of the study is to investigate the lateral deflection, bending moment of pile group under the simultaneous action of axial and lateral loads. The incurring soil reaction due to the lateral resistance of piles when the lateral load is applied is also determined, envisaging the importance to study the p-y curves at various depths. The statistical variation in the form of probability density function and cumulative density function of the pile bending moments and lateral deflections are evaluated. The numerical responses indicate that the parameter uncertainty of the soil properties and their coefficient of variation play a substantial role in the depiction of magnitudes of bending moment and lateral deflection.