水平循环荷载下海洋腐蚀损伤桩基承载变形特性演化规律与时变可靠度研究

海洋环境服役桩基长期遭受海浪、潮汐及海冰等周期性水平循环荷载与海水腐蚀的耦合作用，继而导致桩基刚度的退化及桩周土的循环弱化，严重影响了海洋环境服役桩基的水平承载性能与服役安全性。因此，有必要对海洋环境下桩基水平承载变形特性与服役可靠性进行系统研究。本项目研究针对海洋环境下桩基的服役环境特点，通过开展模型桩室内模型试验、理论解析和数值模拟研究，分析研究水平循环荷载与海水腐蚀耦合作用下桩基腐蚀疲劳损伤机理，建立其腐蚀疲劳损伤理论模型；探讨水平循环荷载下腐蚀损伤桩基承载变形特性演化规律，建立水平循环荷载下腐蚀损伤桩基循环p-y曲线分析模型；构建水平循环荷载下腐蚀损伤桩基振动微分方程，建立其水平动力特性分析模型；探讨水平循环荷载下腐蚀损伤桩基失效模式，建立其水平承载时变可靠度分析模型。本项目研究成果可为海洋环境服役桩基设计、加固修复及安全可靠性评估提供重要的理论指导与评价依据。

Pile foundation served in marine environment is subjected to the long-term coupling effect of periodic lateral cyclic loading such as waves, tides and sea ice and seawater corrosion, which results in the degradation of pile stiffness and cyclic degradation of soil around the pile, and seriously affects the lateral bearing capacity and service safety of pile foundation in marine environment. Therefore, it is essential to conduct the systematic research on the lateral bearing deformation behavior and service reliability of pile foundation in marine environment. In view of the service environment characteristics of pile foundation in marine environment, by conducting the indoor model tests on model piles, theoretical analysis and numerical simulation, the corrosion fatigue damage mechanism of pile foundation under the coupling effect of lateral cyclic loading and seawater corrosion is studied. The theoretical model of corrosion fatigue damage of pile foundation under the coupling effect is established. The evolution law of bearing deformation behavior of corrosion-damaged pile foundation under lateral cyclic loading is investigated, and the cyclic p-y curve analysis model of corrosion-damaged pile foundation under lateral cyclic loading is established. The vibration differential equation of corrosion-damaged pile foundation under lateral cyclic loading is developed, and the analytical model of lateral dynamic behavior of corrosion-damaged pile foundation is proposed. The failure mode of corrosion-damaged pile foundation under lateral cyclic loading is investigated, and the time-dependent reliability analysis model for lateral bearing behavior of corrosion-damaged pile foundation is established. The research results of this project can provide important theoretical guidance and evaluation basis for design, strengthening and rehabilitating, and safety reliability assessment of pile foundation served in marine environment.