斜式结构上海冰爬坡和堆积的机理和控制研究

The sea ice climbing and rubbling on the inclined structure is one of the key issues in the study of the interaction mechanism of the sea ice and the inclined structure. In this proposed research project, theoretical analysis and numerical simulations are jointly performed for studying on this basic problem: first of all, through the abstraction and simplification for the process of the sea ice climbing and rubbling along the inclined structure, a theoretical mechanics model of the entire climbing and rubbling process is systematically established and verified. The methodologies for calculating the climbing height and pile-up height of the ice is studied, and the variations of the parameters related to sea ice climbing and rubble pile are analyzed. Secondly, a detailed three-dimensional numerical model of the interaction of the sea ice and the inclined structure is established and verified. The evolution process and contour change of the ice accumulation is investigated, and the relationship between the structural width, the sea water depth, and the ice accumulation is explored. The influence of the sea ice climbing and rubble pile on the ice load is then studied. Based on the research of the mechanism of the sea ice climbing and accumulation on the inclined structure, new measures to control the sea ice climbing and rubble pile are proposed. The efficiency of the new measures is verified through the numerical simulation method. This research project has important scientific significance and practical value to enrich and develop the basic theory of disaster prevention and reduction of offshore engineering in cold regions (or polarregion) in China.

斜式结构上海冰爬升和堆积的问题是研究海冰与斜式结构相互作用力学机制热点问题之一。本项目针对这一基础问题，采用理论分析和数值模拟相结合的方法开展研究：首先，通过对海冰沿斜坡爬升和堆积的过程进行抽象和简化，系统地建立斜式结构上海冰爬坡和堆积的全过程力学理论模型，并进行模型验证，研究海冰爬坡高度和堆积高度的计算方法，分析与海冰爬坡和堆积相关的参数变化规律；其次，进行海冰与斜式结构相互作用的精细化三维数值模型的建立以及模型验证，考察海冰堆积的演变过程及轮廓变化，探讨结构宽度、水深和海冰堆积形成的关系，研究海冰爬坡和堆积对斜坡结构上海冰荷载的影响。基于斜式结构上海冰爬坡和堆积的机理研究，提出控制海冰爬坡和堆积的新型构造措施，利用数值模拟方法考察新型构造措施的效率性。本项目的研究对于丰富和发展我国在寒区（极区）海洋工程防灾减灾基础理论，有着重要的科学意义和实用价值。

本项目首先基于半无限弹性地基板理论，考虑海冰破坏模式、弯曲受压区和浮力作用的影响，建立了海冰沿斜坡爬升和堆积的全过程力学理论模型。基于理论模型，提出了冰板失效比的概念，给出了海冰堆积高度计算方法，利用现有经验公式验证了提出的理论模型，从理论解释了斜式结构海冰爬升和堆积形成科学问题，发现了结构倾角、上部海冰堆积倾角、冰物理力学指标（弯曲强度和抗压强度，及弹性模量）、冰厚、冰与结构摩擦系数、冰与冰摩擦系数等参数对海冰堆积的影响规律，揭示了斜体结构海冰堆积力学机理。基于有限元软件建立了海冰与斜体结构相互作用三维精细化数值模型，通过试验和现场观测数据验证了数值模型可靠性。基于数值模型，进行了斜体结构与海冰相互作用过程仿真，给定了宽体和窄体斜体结构界定值，数据拟合了结构倾角和海冰上部堆积角的关系式，分析了斜体结构海冰动冰力，发现了锥体结构曲面的曲率对海冰作用力的影响规律，解决斜体结构海冰堆积工程计算应用问题。基于斜式结构海冰堆积机理的系统研究，提出了抑制海冰爬坡和堆积的新型构造和控制方法，如：斜面结构上半齿状半弧形凸起体构造；可移动式锥体平台结构破冰棱锥体等。新型构造的提出，可有效解决斜体结构海冰堆积问题，具有现实工程应用意义。