中文摘要：

近海管道通常被掩埋起来以避免渔业捕捞活动的损伤，并且能够为管道提供隔热保护．如果管道能够由沟槽提供足够大的侧向力，管道将会由于温度变化或其它原因引起轴向力的增大而发生隆起屈曲．如果没有挖沟线等侧向约束，侧向屈曲将会占据主导地位．管道轴向应力是导致海底管道发生屈曲的主要原因．侧向屈曲在较低的压力下比隆起屈曲更容易发生．双层管的复杂结构导致其整体屈曲理论分析十分困难．利用小尺寸模型实验装置对双层管道整体屈曲进行了实验研究，得出屈曲发展过程中轴力与位移的关系以及临界轴力．此外，利用最新的管中管单元技术，建立了高效的有限元分析模型，并且对管道屈曲前和屈曲后全程进行了模拟．对比表明数值模拟结果与实验结果非常吻合．

英文摘要：

Offshore pipelines are usually buried to avoid damage from fishing activities and get thermal insulation. Provided that the pipelines are sufficiently confined in the lateral direction by the passive resistance of the trench walls, they may be liable to upheaval buckling caused by rise in axial force due to temperature changes or other factors. Unless lateral restraint is provid- ed, by trenching the line, for example, lateral buckling will be dominant. The axial compressive force is the primary cause of pipeline buckling. Lateral buckling takes place at a lower axial compressive force than upheaval buckling. The complex structure of the pipe-in-pipe （PIP） sys- tem makes global buckling difficult to tackle by theoretical analysis. An experimental study of the global buckling of pipelines was conducted by means of a small-scale model test apparatus. Results were presented for several tests involving both the relationship between the axial force and displacement and the critical axial force. Futhermore, the efficient finite element model was used to simulate the pre-buckling and post-buckling states of the pipeline with the latest tube-to-tube technology. The comparison shows that the numerical simulation results agree well with the experimental ones.