中文摘要：

海底埋设双层管管道隆起屈曲分析是海洋管道设计的重要技术之一。在管道隆起屈曲分析中实现管土作用和内外管相互作用的准确模拟一直是工程应用追求的目标，也是其中的难点。利用管土作用单元和管中管单元等技术，建立了海底埋设双层管管道隆起屈曲分析有限元模型。该模型不但考虑了管道初始形状、压力、温差载荷、管道材料非线性等常规因素，还考虑了非线性管土作用和内外管相互接触作用，并能对管道屈曲前和屈曲后全程进行模拟。应用该模型，计算了一条高温高压埋设双层管管道隆起屈曲过程中的应力等。算例表明该模型有较好收敛性，能对一般海底高温高压埋设双层管管道隆起屈曲进行准确模拟。

英文摘要：

Upheaval buckling analysis of buffed subsea pipe-in-pipe （PIP） pipeline is one of important technologies to design the submarine pipeline. Accurate simulation of the pipe-soil interaction and the inner-outer pipe interaction is the goal of the engineering application and also the difficulty of the upheaval buckling analysis. Based on PSI elements and tube-to-tube elements and so on, a finite element （FE） simulating model is proposed for the buffed suhsea PIP pipeline upheaval buckling analysis. This model not only takes account of conventional factors, such as initial imperfection, pressure, temperature change, material nonlinearity, but also the nonlinear pipe-soil interaction and the inner-outer pipe interaction. It could simulate the whole buckling process of a pipeline, including before-buckling and post-buckling behavior. The stresses of a high temperature/high pressure submarine buffed PIP pipeline are calculated by using the proposed model. The results indicate that the model has a good convergence and can simulate the upheaval buckling of a high temperature/high pressure submarine buried PIP pipeline accurately.