【作者】 胡忠璜；

【导师】 张日向；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2007， 硕士

【摘要】 负压桶形基础作为一门新技术早在50年代就开始为各国学者所研究，90年代首次应用于挪威北海平台。桶形基础平台结构是一种全新概念的平台，突出问题是要解决“下得去、立得稳和拔得稳”三大技术难题。本文系统的研究了浅海桶形基础水平承载力计算分析的方法和各种破坏模式下的计算公式，主要解决浅海桶形基础在海上安装建成后“立得稳”的问题。本文根据辽河油田浅海区域海南8#、24#井位，提出适合该地区特点的浅海桶形基础平台水平极限承载力的分析方法和计算公式，并且分析了桶形基础在受横向荷载作用下的三种失态模式，利用目前应用较为广泛的有限元软件ANSYS对桶形基础进行有限元分析。通过使用ANSYS软件，对桶基基础与周围土体相互作用进行有限元数值模拟。土体采用Drucker-Prager弹塑性和相关联流动准则，桶形基础作为线弹性体考虑，基础与土的相互作用采用二维面面接触单元模拟，将重力场转化为初始应力荷载施加于每个单元上，实现模型中的初始重力场。建立桶基和土体的相互作用的模型，在基础与土的交界面上建立面面接触单元，将基础界面定义为目标面，将土体界面定义为接触面，在实体单元的外表处生成目标单元和接触单元，形成接触对。选用targe170和conta174来模拟桶基与土的接触作用。然后利用接触分析的算法与其它计算公式所得结果进行综合分析比较，探讨影响水平承载力的因素。最后通过桶基处于砂土、粉质粘土以及粉土情况下的分析，研究不同土体特性指标下的水平承载能力，为在浅海应用桶形基础平台提供了参考依据。更多还原

【Abstract】 Suction caissons of bucket foundation as a technique was studied by scholars in 50’timesand was first applied in platform of Norway North Sea in 90’times. Bucket foundationproduction platform is a new type offshore platform, whose main problem is to solve threetechnical difficulties which contain the possibility of bucket foundation penetration duringbuilding, the stability during work and the possibility of pulling out during removal. Thepurpose of this paper is to analyze the method of calculating horizontal bearing capacity ofbucket in shallow sea, and the calculating formula in different failure modes, and to solve theproblem of stability during the platform working as major workAccording to the characteristics of the No. eight and twenty-four location in Oil Field ofLiaoHe, this paper gives the method of analyzing and equation of calculating are proposed forhorizontal bearing capacity of bucket foundation, analyzes the three of fail method on thehorizontal force of bucket foundation is analyzed, and give finite element analysis on bucketfoundation can be conducted by the ANSYS software which is popularity in the world now.Numerical simulation of finite element method for bucket foundation under horizontalforce was conducted by making use of ANSYS software. The nonlinear stress-strainbehaviors of soils were modeled via Drucker—Prager type and associative flow rule, and thefoundation was treated as linear-elastic material, while soil-foundation interaction wassimulated via setting contact elements at interface between soil and foundation. Bytransforming gravity field into initial stress state on each element, the initial gravity field wascarried out.After creating the model of interaction between bucket foundation and soil, establishingcontact element in the interface between foundation, defining the foundation interface as thetarget area, defining the soil interface as the contact area, then target unit and the contact unitwill appear in the surface of entity unit, simulating interaction between bucket foundation andsoil with the targe 170 and conta174. We can compare the result of the method by algorithm ofcontact to other methods. The factor of impacting horizontal bearing capacity of bucket isdiscussed, which can be available for bucket foundation in shallow sea.更多还原