Finite Element Analysis And Rational Structure Pattern Research For Offshore Single-Pile Platforms

The marginal oil field was thought that had less value in commercial exploitationpreviously, but in recent years, with the demand of energy enlarging rapidly in theworld, all eyes begin to focus on it. There are abundant petroleum resources in thewide continental shelf in our country;however, most of them are marginal oil fields inshallow seas. So development of the minimum offshore platform for marginal oilfields has become the hot subject which domestic petroleum enterprises would payclose attention to at present.As one been widely used pattern of minimum structures, single-pile platform hasa good application prospect because of its advantages such as short building cycle,little steel spending and quick installation on site. But under the extreme environment,the topside structure of the platform would have a remarkable deflection. This notonly influenced normal production, but also had a potential hazard of damage. Thepurpose of this paper is to study the structure of single-pile platforms and control thetopside deflection. Additionally, a rational structure of pile foundations was designedto meet the demand of safety in production.Based on the Winkler hypothesis, and with the help of finite element analysisprogram -ANSYS, this paper could simulate the nonlinear behavior between the pileand the soil by using concentrated COMBIN39 spring element and apply the P-ycurve method in Computer Aided Engineering software for the first time. After settingup three-dimensional finite element models of CB11H, CB30B and CB32A, thispaper performed static and transient dynamic analyses for the 3 platforms in normalproduction, extreme wave and extreme ice conditions, and find a feasible way toreduce the deflection of topside structure. Through comparing the effect of increasingdiameter, reinforcing foundation, adding steel and changing diameter, a scientificdeflection controlling method and a rational pattern of the pile have been put forward.Further more, a model pile test has been held to verify the feasibility anddependability of the numerical simulation method in this paper.So, this paper has an important practical value and innovative meaning inresearching the offshore platform under remarkable environmental lateral loadings,especially for the single-pile minimum platform.