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 elastoplastic 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.