Response Analysis Of Submarine Pipeline Subjected To Seismic Waves

With the increasing of human demand for energy,marine oil industry has made rapid development.Submarine pipeline as safest and most economical way to transport offshore oil and gas plays an irreplaceable role.The issue of security of submarine pipeline has been widely studied due to complex underwater environment surrounding submarine pipelines,expensive cost and serious environmental pollution caused by accidents.Earthquake as a catastrophic disaster has an important influence on submarine pipelines.There are lots of research on the response of buried pipeline under the earthquakes,but limited research on the submarine pipeline No seismic code for submarine pipeline design is presented until now.It is of great significance to analyze the dynamic response of submarine pipelines subjected to seismic waves.Based on a natural gas transmission submarine pipeline project,a summary of codes for seismic design of buried pipeline is carried out.Using ANSYS the finite element(FE)model of the long-distance pipeline is established.The responses of the global buried pipeline and the local free spanning pipeline are analyzed under seismic waves,respectively.The contents of the research include:1.A comparison of seismic design codes between submarine pipeline and onshore pipeline is performed.Based on the research results of submarine pipeline and onshore buried pipeline,seismic analysis methods including theoretical methods and numerical methods are discussed.2.The relationship between the hydrodynamic coefficients and the seismic coefficients is analyzed.Based on Morison equation,the FE model of a local free spanning pipeline is established to analyze the dynamic response of submarine pipelines subjected to earthquakes.Considering the factors of earthquake amplitudes and soil types,the permissible spanning length is calculated.3.The global finite element model for a buried submarine pipeline is established.The FE model is divided into nine segments according to geological conditions.Considering the effects of spatial variation and traveling wave of seismic waves,the dynamic response of the buried submarine pipeline is performed.