Study On Seismic Design Method For Buried Oil And Gas Pipelines Across Faults

Oil and natural gas are important energy sources for human production and national strategic security.Oil and gas transmission pipelines are also an important part of the lifeline system.Many oil and gas pipelines that have been put into operation and planned for construction in China have crossed the high-intensity seismic zone,and the pipeline is threatened by the seismic damage of seismic faults at any time.The research on seismic design method of cross-fault pipelines has become one of the hotspots of seismic research in lifeline engineering.This paper starts with the seismic damage response of oil and gas transport pipelines under the action of seismic faults in high-intensity areas,and compares the seismic design methods of cross-fault oil and gas transport pipelines in the world,combined with the theory and conclusions completed by the research group.The experimental research results,using the finite element numerical simulation method,focus on the comparison between the design method and the finite element method in the current seismic engineering code of China's oil and gas pipelines,and propose the proposed correction coefficient of the normative method,and on this basis Seismic measures for fault pipelines were studied.The main contents of the paper are as follows:1.The importance of the seismic design of oil and gas pipelines to national strategic safety is introduced.The historical examples of oil and gas transmission pipelines suffering from seismic faults are explained,which indicates that fault dislocations are the main cause of damage to oil and gas transmission pipelines,and analyze various factors affecting pipeline response under fault dislocations.2.The results of theoretical model research,numerical simulation research and experimental observation research of seismic design of trans-fault pipelines by domestic and foreign researchers are listed,and the theoretical and experimental results completed by the research team are summarized.It focuses on the recommendations and regulations for seismic design of cross-fault pipelines in China's seismic design codes for pipelines,laying the foundation for subsequent research.3.Through the finite element numerical simulation software,the simulation analysis is carried out on the bedrock site,the thickness of different overburden layers,and different crossing angles to calculate the maximum tension and compression of the oil and gas transport pipeline under the fault.The compressive strain is compared with the improved Newmark-Hall method adopted in the specification.Based on this,the proposed correction coefficient of the normative method is proposed.4.Through the study of the depth and width of pipe trench excavation,the selection of backfill materials and the setting of elbows,the effects of various seismic measures on the stress and strain of oil and gas transport pipelines under fault dislocations,useful suggestions are provided for the seismic design and construction of the pipeline.