Critical Suspended Length of an Inshore Pipeline under Wave Conditions

摘要

This paper analyzes the critical suspended length of an inshore pipeline which is anchored straight on the seabed. Pipe suspended length determines the static load and dynamic response of the pipe, playing an important role in the stability of submarine pipeline. Thus, with the CAM static theorem, the allowable suspended length of the pipeline is calculated. The results show that the suspended length due to seabed depressions can be far longer than that due to submarine obstacles. Also, study for the vortex-induced vibration (VIV) of the pipeline is carried out to avoid that resonance vibration happens between pipeline and wave; the allowable range of the pipe span is compute with the CAM dynamic theorem. To get a more reasonable critical suspended length, two kinds of finite element span models are built according to the location of pipe span. With the software ANSYS, the models are analyzed under wave conditions. The results reveal that the critical suspended lengths differ in the two models; the location and value of the biggest flexural stress on the pipeline vary according to the anchor span (distance between two anchors).