中文摘要：

倒T型导管墙桩基防波堤作为新型港工结构，主要依靠桩基和自身重力维持稳定。以天津港水文地质条件为算例，建立三维弹塑性有限元模型，通过荷载一位移关系曲线，确定稳定性安全系数。分析极限状态下桩基沿环向与竖向的土压力分布，得出桩侧极限水平土抗力，并将有限元结果与美国规范API土抗力计算方法进行比较。造成防波堤结构失稳的原因主要有两个，即结构自身无法满足强度要求和土体达到极限。结构自身强度达到极限时，可用p-y曲线有限差分迭代法求取安全系数：土体达到破坏极限时，可分别假定转动点位于桩轴线上和偏离桩轴线两种情况，利用极限平衡法，建立抗倾稳定性简化计算方法。经验证，理论方法得到的稳定性安全系数与有限元结果比较接近。

英文摘要：

The inverse T type breakwater with jackets and pile foundations is a new type of structure applied to port and coastal engineering, of which the stability is sustained by pile foundations and gravity. In terms of the hydrogeological conditions of Tianjin Port, a 3D elastoplasfic finite element model is estabilished for stability analysis of the inverse T type breakwater with jackets and pile foundations. The safety factor of stability is determined by P-S curve. The soil resistance is calculated by analyzing the vertical and circumferential distributions of earth pressure on pile foundations in the limit state. Besides, the earth resistance calculated by the finite element method is compared with API. There are two main reasons which cause structural instability： Firstly, the structure itself is unable to meet strength requirement; Secondly, the soil is in the limit of state. For the first reason, calculate the safety factor of stability by p-y curve method. When the soil is in the limit state, simplified methods for anti-overturning stability based on the rotation point which is on the pile axis or deviates from the pile are set up. In comparison to finite element method, simplified calculation method is reliable.