Researches On P-y Curve Of Large Diameter Piles Under Lateral Loadings

The p-y curve method has been increasingly considered as a rational method foranalyzing laterally loaded piles in recent years, the elasto-plastic proceeding ofsoil-pile interaction can be embodied in this method. The key to application of thismethod is chosing a series of rational soil springs and suitable parameters about thep-y curve .With the fast development of high buildings and long span bridges , largediameter piles have been applied more extensively. So a deep research on p-y curvesof large diameter pile is peremptorily in needed.In this paper ,numerical method is employed to study lateral behavior of largediameter piles. soil-pile system is modeled by a three dimensional nonlinear numericmodel of the coupled finite element—infinite element—contact interface element .p-y curves are back fit by nonlinear least squares approach.Researches on p-y curves of large diameter piles are processing from fourfactors:soil friction angle, soil cohesion ,soil unit weight and pile diameter. Based onthe result,the rule about p-y curves of large diameter piles is summed up. p-multiplieror y-multiplier which accounts for the loss of soil resistance due to the group"shadowing" effect is employed to make the p-y curve of single extensively apply topile group.In this paper, the effect on the tip pile displasment and the effect on thevalue of p-multiplier or y-multiplier about each pile within group are discussed fromdifferent pile spacing and different pile amount.