Analysis Of The Influence Of Surcharge On Buried Pipeline In Soft Soil Area

With the increasing density of urban pipeline network in China and the further development and utilization of oil and gas resources in Western China,the density of oil and gas pipeline network is bound to increase.Generally,the buried depth of buried pipelines is shallow,which is easily affected by engineering activities.In recent years,the accidents of pipeline deformation and damage caused by heaped load have occurred from time to time.At the same time,under the premise of poor engineering characteristics of soft soil,this paper studies the influence of surcharge on buried pipelines in soft soil area.Three methods,theoretical analysis,theoretical calculation and numerical simulation,are used to analyze the deformation and failure mode of pipeline under surcharge load.The main research results are as follows:(1)Based on the research on the interaction between foundation and foundation,the deformation and failure modes of pipeline under the action of surcharge are summarized.The soil under the surcharge is mainly analyzed in three areas.In area I,the pipeline mainly produces vertical displacement,while in areas II and III,the horizontal and vertical displacement,and the vertical displacement gradually decreases with the distance from the surcharge.Secondly,according to the factors that affect the deformation of pipeline Through the analysis of the factors,this paper mainly studies the height of the reactor carrier,the horizontal distance between the reactor carrier and the pipeline,and the buried depth of the pipeline.(2)Based on the Winkler elastic foundation beam theory and the busnersk solution,the vertical displacement of the pipeline is analyzed,and the influence of three factors on the deformation of the pipeline is analyzed.That is,with the increase of buried depth and the distance between the pipeline and the pile carrier,the vertical displacement of the pipeline decreases;with the increase of pile height,the vertical displacement of the pipeline also increases.(3)Using the numerical simulation software,the deformation of the pipeline and the soil around the pipeline is analyzed.The results show that the existence of the pipeline restricts the deformation of the soil on the upper part of the pipeline to a certain extent,and the soil on the upper part of the pipeline tends to move to both sides of the pipeline.It is verified that there is relative displacement between pipeline and surrounding soil in soft soil area.At the same time,it also verifies the rationality of the soil partition under the pile carrier in the third chapter.(4)By using the numerical simulation software,the three influencing factors of pipeline deformation are analyzed,and the conclusion is the same as the theoretical calculation result.When analyzing the horizontal displacement of the pipeline,it is found that the horizontal displacement of the pipeline reaches the maximum at the edge of the reactor carrier,and decreases on both sides,and the overall trend is that the horizontal displacement of the pipeline increases with the distance from the reactor carrier It increases first and then decreases.The theoretical analysis is verified.The buried pipeline affected by the reactor carrier is determined to be within the range of one time of the width of the reactor carrier.(5)Based on the previous analysis theory,the deformation and failure case of an oil pipeline is inversed.Through theoretical calculation,it is found that the pipeline has a large lateral displacement deformation and a small vertical displacement,which is in line with the previous analysis.Moreover,it is analyzed with the yield curvature and yield bending moment of this type of pipeline,which has produced deformation and failure.According to the displacement vector diagram,the deformation mode of the foundation soil is consistent with the field situation.(6)Based on the previous theoretical analysis and numerical simulation,this paper puts forward the temporary prevention and control measures of pipeline deformation caused by surcharge,and puts forward the permanent protection measures of pipeline from two aspects of temporary prevention and control measures and predictive protection measures.(7)Based on the theoretical analysis and numerical simulation of the reactor carrier influence range,and the analysis of the pipeline displacement trend,the pipeline monitoring suggestions are put forward from the determination of monitoring range,the layout requirements of monitoring points,the suggestions of monitoring content and the processing of later monitoring data.This paper contains 61 figures,14 tables and 86 references.