Numerical Analysis Of Effects Of Spudcan Penetration Into Clay On P-y Curves Of An Adjacent Laterally Loaded Pile

When a jack-up rig works near a jacket platform,large-diameter spudcan foundations need to be penetrated into the seabed to provide bearing capacity for its operation.Additional pile response will be induced by soil squeezing due to spudcan penetration.Therefore,the impact of spudcan penetration on the adjacent platform pile needs to be evaluated objectively.It has been shown that during spudcan penetration into the stratum,p-y unloading of the adjacent laterally loaded pile can be observed,and when the spudcan moves far away,the p-y curve reloads again.Therefore,the variation of the p-y curves of the adjacent laterally loaded pile during spudcan penetration into the clay at different spudcan-pile clearances(the nearest distance between the edge of the spudcan and the edge of the adjacent pile)and penetration depths is investigated by the CEL(Coupled-Eulerian-Lagrangian)finite element method.Research conducted and relevant conclusions are as follows:(1)Within the working conditions and pile head loading conditions involved in this study,it is found that with the decrease of the clearance between the spudcan and the adjacent pile,the p-y curves of the adjacent laterally loaded pile include a complete evolution of unloading,reverse loading and reverse unloading and reloading,and the effects of spudcan penetration on the p-y curves of the adjacent laterally loaded pile are relavant to the spudcan-pile clearance and the penetration depth.When the clearance increases to 0.5 times the maximum spudcan diameter,the p-y curves of the adjacent laterally loaded pile only show unloading and reloading.(2)In order to represent the effect of spudcan penetration into clay on the p-y curves of the adjacent laterally loaded pile at different clearances and different spudcan penetration depths,an influence coefficient is introduced,which is defined as the ratio of the soil pressure considering the influence of spudcan penetration corresponding to the relative displacement of the same pile-soil to the soil pressure recommended by the API code,and the variation of the influence coefficient with the clearance and spudcan penetration depth is investigated.Further,by comparing the pile response with and without considering the effect of spudcan penetration on the p-y curves of the adjacent laterally loaded pile,the necessity of considering the effect of spudcan penetration on the p-y curve of the adjacent laterally loaded pile is clarified.(3)Further,the relationship between the influence coefficient versus depth with different spudcan diameters,clay strengths and adjacent pile diameters is analyzed,and the results show that the trend of the influence coefficient with depth was consistent when the parameters are changed,and the relationship between the influence coefficient with depth was suggested for different clearances and penetration depths,and the relationship established was verified by centrifugal model tests when the spudcan penetrating into clay,and the relationship is proved reliable reflection of the pile-soil interaction during spudcan penetration into clay.