Numerical Assessment of Laterally Loaded Pile Group Efficiency

The key factors governing the lateral response of a pile group include the pile-head connection rigidity, the pile-soil relative stiffness, the pile spacing ratio, the pile group size and the pile/soil nonlinear response. Since the earlier experimental observations of the existence of group effects it is commonly assumed that the efficiency of a pile group is less than unity and group effects tend to disappear for spacing ratios larger than 6–7. Despite the availability of advanced computational tools, laterally loaded groups are studied in practice via BNWF approaches and researches about the assessment of the pile group efficiency as a function of the displacement level (i.e. load level) are extremely limited. This paper is aimed at numerically evaluating the influence of displacement level, spacing ratio and pile group size on the lateral efficiency of in-line pile groups in a sandy soil. This will be done by using both a BEM code recently developed by the authors and a more advanced and rigorous commercial code. Presented results may be useful for the design of laterally loaded pile groups in a displacement-based design approach.