Bearing Capacity And Deformation Analysis Of Laterally Loaded Offshore Single Pile

In recent years,with the continuous exploiture of offshore resources,more and more ocean engineering projects have appeared in China,such as cross-sea bridges,offshore drilling platform,offshore wind turbines and so on.And pile foundation was widely used in such projects due to its advantages such as simple constructor,high bearing capacity,small settlement,etc.The offshore piles were often subjected to the horizontal cyclic load caused by wind or wave.What's more,the horizontal displacement of offshore piles would be accumulated and increased due to the long-term cycle lateral load.And that may influence the proper functioning of the superstructure.Therefor,based on the existing research achievements and supported by the National Natural Science Foundation of China?NO:51578231&51378197?,the bearing capacity and deformation of laterally loaded offshore single pile was studied by theoretical analysis and numerical simulation in this paper.And the main research work was outlined as follows:At first,the maximum radial stress of the soil around the laterally loaded pile(shear stress?_r?=0)was obtained according to the stress distribution of soil.So,the stress equilibrium differential equation of the soil around the pile shaft was solved by introducing the stress boundary condition,and the stress increment solution of soil along the pile-soil interface was given to analyse the lateral resistance of soil around the pile shaft.And the effect of longitudinal stress change on soil resistance was also considered to set up the p-y curve of laterally loaded single pile.The solutions from the presented p-y curve were verified by comparing the calculated results with the available experimental data.Based on these,the influence rule of cohesion,internal friction angle and elastic modulus coefficient of soil on the p-y curve and ultimate lateral resistance of soil was obtained by the parametric analysis.Secondly,the 3D numerical model of single pile under horizontal load was set up by the finite element software ABAQUS,and the degradation stiffness model of sandy soil under cycle load was realized in the numerical model by the user subroutine USDFLD of ABAQUS.The reliability of the numerical model was validated and the offshore single pile under the cyclic horizontal wave load was studied by the numerical model.And the influence rule of wave height,wave period,depth of the water and the number of wave load on the cumulative horizontal displacement of pile shaft was analysied.Finally,the influence of pile diameter and penetration depth on the cumulative horizontal displacement of single pile under cyclic horizontal wave load was analysied based on the numerical model,of which the results may provide reference for the design of pile foundation in offshore engeneering.