【作者】 张连丽；

【导师】 谢世楞； 王元战；

【作者基本信息】 天津大学 ， 港口、海岸及近海工程， 2013， 博士

【摘要】 在我国沿海地区广泛分布着软土地基，倒T型导管墙桩基防波堤与板格形导管架桩基码头，作为适用于软土地基的新型结构，具有整体性好，结构重量轻，工程造价低，施工简便等优点，但结构的承载机理与破坏模式尚不明确，稳定性分析尚无规范可循。本文采用有限元数值模拟方法与理论方法，对两种新型结构的承载特性及稳定性分析方法进行研究。（一）倒T型导管墙桩基防波堤1．建立了倒T型导管墙桩基防波堤结构与地基土体相互作用的三维弹塑性有限元模型，对结构的承载特性及破坏模式进行研究，根据荷载—位移关系曲线以及失稳判别准则确定稳定性安全系数。2.对极限状态下倒T型导管墙桩基防波堤桩侧沿环向、竖向的土压力分布情况进行分析，计算桩侧极限水平土抗力，并与API公式的计算结果进行比较。3.根据不同的失稳破坏模式，对倒T型导管墙桩基防波堤稳定性提出了不同的简化分析方法。针对地基破坏致使结构发生失稳的情况，建立了防波堤结构竖向承载力与抗倾稳定性的简化分析模型；针对桩身屈服致使结构发生失稳的情况，建立了基于p-y曲线法的稳定性简化分析方法，并通过塑性铰判别准则，得出结构稳定性安全系数。4.分析了底板宽度、桩径、桩距、桩基入土深度对防波堤结构稳定性的影响规律，综合考虑结构稳定性要求、强度要求以及材料用量，提出了倒T型导管墙桩基防波堤结构尺度确定原则。（二）板格形导管架桩基码头1.建立了板格形导管架桩基码头结构与地基土体相互作用的三维弹塑性有限元模型，通过加载系数法与强度折减法模拟了结构的极限状态，对结构的承载特性与失稳模式进行分析，得出稳定性安全系数。2.对极限状态下陆侧导管架外壁、海侧导管架外壁、导管架内壁上的土压力大小及分布规律进行分析，并与Rankine主、被动土压力进行比较。3.根据结构特点及受力模式，建立了码头结构竖向承载力及抗倾稳定性的简化计算方法。根据加载系数法与强度折减法的基本原理，计算稳定性安全系数，并与有限元法进行比较。更多还原

【Abstract】 Soft clay constitutes the majority of the ground in the coastal areas of China. Boththe inverse T type breakwater with jackets&pile foundations and pile-supported platepanel jacket wharf are new type of port structures, which adapt to soft ground. Thenew structures have features of good integrity, light weight, less cost and convenientconstruction. Nevertheless, the working mechanism and failure pattern for the newstructures remain unclear, and there is no rule to follow for stability analysis. In thispaper, a series of research work have been carried out on bearing capacity andstability analysis of the new structures by using the methods of theoretical analysisand finite element numerical calculation. The main contents are as follows:The main contents about the inverse T type breakwater with jackets&pilefoundations:1. A3D elastic-plastic finite element model was estabilished for stability analysisof the inverse T type breakwater with jackets&pile foundations. Furthermore, thebearing mechanism and failure mode were made clear, and the safety factor ofstability was determined basing on the criterion of instability and P-S curve.2. Analyze the vertical and circumferential distribution of earth pressure on pilefoundations in the limit state, by which the earth resistance was calculated. Besides,the earth resistance calculated by finite element method are compared with thecalcultion mehod of ultimate earth resisitance in API.3. According to different instability modes, simplified calculation methods forstability analysis of the inverse T type breakwater with jackets&pile foundationswere presented here. In the case of soil failure, simplified calculation methods forvertical bearing capacity and anti-overturning stability were set up; In the case of pilefailure, the bearing capacity simplified calculation method was established basing onp-y curve method and criterion of “Plastic hinge”.4. Analyze stability of the inverse T type breakwater with jackets&pilefoundations in different member size, such as width of the bottom plate, diameter ofthe pile, distance between piles, and depth of the pile penetrated in soil. Consideringthe stability and strength requirement, and cost as well, the principle of determiningdimensions of the inverse T type breakwater with jackets&pile foundations wasproposed. The main contents about piled-supported plate panel jacket wharf:1. A3D elastic-plastic finite element model was estabilished for stability analysisof piled-supported plate panel jacket wharf. Furthormore, the structural limit failurestate was simulated by loading coefficient and strength reduction method, and thebearing mechanism and failure mode were analyzed.2. Analyze the magnitude and distribution earth pressure on plate panel jacket inthe limit state. Besides, the earth pressures calculated by finite element method werecompared with Rankine active, passive earth pressure.3. According to the structural characteristics, simplified calculation methods forvertical bearing capacity and anti-overturning stability were estabilished. Based onloading coefficient and strength reduction method, the safety factors were calculated,and the results were compared with the one calculated by finite element method.更多还原