随着海洋油气资源开发力度的加大，特别是海洋工程设施不断增加，海洋工程阴极保护防腐技术也得到了快速发展，并广泛运用于海洋工程防腐实践中。但由于海洋工程设施，特别是海洋石油平台导管架体积庞大、结构复杂且所处的海洋腐蚀环境复杂多变，其阴极保护设计经常出现问题。如果防腐措施和阴极保护系统设计不当，过保护时将导致牺牲阳极过量，加大结构负荷，造成投资浪费；欠保护时将严重影响平台在设计年限的正常运转，大大缩减海洋构筑物的服务期限。因此科学定量评估阴极保护措施的可靠性、准确预测和评估海洋工程设施的腐蚀状态及其阴极保护系统的工作状态，便成为确保阴极保护设计合理、保障建设投资和平台安全、有效延长结构使用寿命的关键技术。研究和探索一种新型有效的阴极保护评估技术，以补充和丰富现有的评估手段，也成为现阶段海洋工程界迫切需要解决的技术难题。边界元技术的发展，为科学评估大型导管架的阴极保护设计和阴极保护状态提供了全新的技术手段。本文重点研究了利用阴极保护数值仿真技术对复杂实体海洋石油平台结构的阴极保护进行评估的技术方法，建立了平台导管架的模型，并在模拟实验水池中开展了实海条件下的阴极保护试验；在建模的基础上，运用边界元技术求解了该导管架模型在阴极保护状态下的电化学腐蚀控制方程，给出了电位分布和电流密度分布。研究获得的仿真计算结果与模拟试验测量结果吻合很好。本研究主要贡献突出在以下几个方面：(1)采用以边界元法为基础的数值模拟仿真技术，给出了在自然腐蚀、电偶腐蚀、阴极保护共存时，平台表面保护电位分布、保护电流密度分布特征，及其三维图像显示，以及牺牲阳极的尺寸及形状随时间变化的图像显示，为海上构筑物的阴极保护评估提供了新的方法。(2)根据平台表面保护电位分布、保护电流密度分布以及牺牲阳极消耗速度的系列模拟仿真计算，实现了平台阴极保护状态的评估和牺牲阳极的剩余寿命预测。(3)建立了平台导管架的模型，在模拟实验水池中开展实海条件下的阴极保护试验，并利用边界元数值仿真技术模拟了钢结构阴极保护状态下的电位分布和电流密度分布。通过将模拟结果和实测结果进行比对分析，验证数值模拟效果。(4)将阴极保护数值仿真技术应用于复杂结构的大型实体导管架，给出了模拟结果，并与阴极保护监测数据进行了对比，验证了该技术的有效性。(5)对钢结构阴极保护初始极化过程的数值模拟方法进行了初步研究，并给出了初步模拟结果，为科学评估阴极保护初期电流设计提供了有益尝试。本论文的研究成果表明利用数值模拟技术开展海洋工程阴极保护设计和评估，技术可行，方法可靠，既可以为阴极保护设计和评估提供参考依据，也补充和丰富了现有的阴极保护评估手段，其有效性在实际应用中得到了验证。With the increasing offshore oil developments and offshore structures, corrosion protectiontechnologies have made a mighty advance，and found a wide application in offshore engineering.However, problems often arise in designing cathodic protection for offshire structures, especially forthe jackets of offshore oil platforms, due to their huge size and structural complexity as well as thevariation and complexity of their ambient corrosion environment. Improper CP designing such asover-protection will increase the structural load with excessive sacrifical anodes and therefore giverise to wasteful investment, while under-protection, on the other hand, will dwindle the seviceduration and pose a threat to the safty of offshore structures. How to quantitatively evaluate effectand reliability of the CP system in scientifical manner and how to predict and evaluate the corrosionof the offshore structures and the working condition of the CP system, therefore, would be vital toensure the feasibility of the CP designing, to guarantee the safty of platforms and constructioninvestment, and to prolong the sevice lives of the structures as well. Moreover, the current oceanengineerings are in urgent need of exploring a new and effective CP assessment technology tosupplement and enrich the existing technologies. The advance in BEM provides a brand-newtechnology for scientific evaluation of the designing and working condition of CP system for bigjackets. In this reaserch, cathodic protection modeling for offshore jacket using the boundaryelement method based on BEASY software was studied. A miniature model offshore jacket wasbuilt and used to test the CP performance in a seawater pool which could simulating tidal beheviorof the sea. Based on the model, BEM was employed to sovle the governing equation of theelectrochemical corrosion of the miniature model offshore jacket under cathodic protection. Themodeling solution of both potential and current density ditribution is presented and compared withthe actual potential measurement of the miniature model offshore jacket, which shows a goodagreement between them. The main contribution of the study is underlined as follows(1) The study of cathodic protection modeling for offshore jacket using the boundary elementmethod was conducted. The potential and current density distribution of the jacket surface,under the coexistence of natural corrosion, galvanic corrosion and cathodic protection, werenumerically modeled by use of BEM, and in this process3D iamge of the two distributions as