【作者】 张建勇；

【导师】 杨树耕；

【作者基本信息】 天津大学 ， 港口、海岸及近海工程， 2005， 硕士

【摘要】 随着近些年全球对能源需求的急剧扩大,原本被认为开发价值不大的边际油田也越来越受到人们的重视。我国广阔的大陆架蕴藏着非常丰富的油气资源,但是已探明的多数海上油田都是位于浅海和极浅海的边际油田,因此研究和制造适合于浅海边际油田开发的简易平台,就成为目前国内石油企业关注的热点课题。作为一种已经得到了广泛应用的简易平台型式,独桩平台凭借其建造周期短、用钢量少、海上施工快捷等优点,具有良好的应用前景。但是在恶劣的海风、波浪、海流和海冰等环境荷载作用下,独桩平台上部结构晃动幅度过大,不但影响了正常作业,还存在着较大的安全隐患。本文的研究目的就是要控制独桩平台的顶部晃动,设计出合理的平台结构型式,满足安全生产的要求。基于这种目的,本文采用通用有限元软件ANSYS,首次将P-y曲线法应用到CAE软件的数值分析当中,利用COMBIN39弹簧单元对桩土间相互作用实现了等效集中的非线性数值模拟,建立了CB11H、CB30B和CB32A三座独桩平台的整体三维有限元模型。通过对平台在正常作业、极端波浪和极端海冰三种工况下,进行静力分析和瞬态动力学时程分析,找到了一条切实可行的减小平台顶部晃动的研究思路。通过对比增大桩径、桩周填石、桩身加筋以及使用变径桩等方法的效果,提出了科学的位移控制措施与合理的平台独立桩结构型式,并且通过模型桩试验验证了本文提出的数值模拟方法的可行性和可靠性。因此,本文对于研究受水平荷载影响效果显著的海洋平台,尤其是独桩式简易平台有重要的实用价值和开拓意义。更多还原

【Abstract】 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.更多还原