Study On Safety Assessment Method Of Suspended Pipeline Under Flood Disaster

With the increasing demand for domestic oil and gas resources,the construction of pipeline network is constantly optimized and improved,and the length of pipeline construction is constantly increasing.But in the process of pipeline construction,it will cross the area where geological disasters occur frequently,may cross small and medium rivers,there is the possibility of flood disasters,resulting in the potential risk of pipeline operation.When the pipeline crosses the river,when the river floods,the pipeline completely exposes the water surface,and the flow of the flood scours the pipeline,causing the pipeline to be suspended,causing the pipeline to bear multiple loads at the same time.Pipeline bears all kinds of loads for a long time,and is prone to pipeline accidents and hidden safety hazards.In order to ensure the continuity and safety of pipeline transportation,it is necessary to accurately assess the safety of suspended pipelines under flood hazards.In this paper,the causes of pipeline suspension under the action of flood are analyzed,and the mechanical analysis of pipeline is carried out.Based on the elastic deformation and plastic deformation of pipeline deformation,the suspended pipeline of yu-ji line under the flood disaster is calculated,and the stress,strain and pipeline deformation of the suspended pipeline are calculated.In this paper,combined with the stress characteristics of the suspended pipeline under the flood disaster and the characteristics of the commonly used finite element software,the finite element software ABAQUS,which is more commonly used to simulate the tube-soil interaction,is selected,which has the tube-soil interaction element.In the calculation process,compile inp source file to calculate stress,strain and deflection.By comparing the consistency between the theoretical calculation results and thefinite element software calculation results,the accuracy of the model was determined.In the numerical calculation process,the model was applied to calculate the stress and strain of the suspended pipeline under different working conditions,and the main factors affecting the stress and strain of the suspended pipeline were analyzed.According to the theoretical calculation results and numerical calculation results,a quick reference table for safety evaluation of the pipeline suspended under flood disaster was established,and the strain calculation process of the pipeline suspended under flood disaster was proposed,and relevant safety evaluation measures were proposed.The conclusion shows that the strength and stability of a section of suspended pipeline under the flood disaster of yu-ji line should be satisfied under the action of flood erosion.For the pipeline that does not meet the requirements of strength or stability,it is necessary to take measures to conduct real-time monitoring of the suspended pipeline in this section,so as to prevent the pipeline from being washed by flood,causing axial rotation of the suspended pipeline and seriously affecting the strength and stability of the pipeline.Based on strain method,the limit strain and allowable strain of suspended pipeline under different working conditions are calculated.ABAQUS finite element software calculation results show that different suspended pipe length,depth,pipeline buried layer soil types and hung up the impending period of different soil layer above the pipeline,the flood flow velocity,the change of the length of pipeline crossing river,lead to pipe stress and strain calculated results,determine the most serious area of dangling deformation,and the corresponding protective measures.