Analysis Of Influence Of Expressway Construction On Buried Oil And Gas Pipeline Safety And Study Of Monitoring Countermeasures

With the expansion of the construction scale of oil and gas pipelines in our country,pipeline leakage accidents frequently occur,which can not only waste resources and pollute the environment,but also may cause serious casualty and great economic loss.Therefore,it is of great practical significance to study the safety impact analysis and monitoring countermeasures of oil and gas pipelines.The damage and leakage of buried oil and gas pipeline caused by expressway construction has become the main dangerous factor that endangers the safety of pipeline transportation.Based on the mechanical theory analysis of buried pipeline,the failure criterion of pipeline is summarized.The negative pressure wave method is used to locate and monitor pipeline leakage,and the negative pressure wave velocity is deduced and corrected to reduce the monitoring error.The research contents and achievements are as follows:Combined with the example of buried pipeline in Xianhubei Highway,the response influence of construction diversion on buried pipeline and the influence of excavator depth on buried pipeline were analyzed by Rhino-Flac3 D simulation.Under the combined action of road traffic load and soil weight,a large vertical displacement occurs on the diversion side of the pipeline,the maximum displacement is 6.9mm,and the direction is vertical downward.At the same time,it has an impact on one side of the pipeline under construction,so that part of the pipeline in the construction section has a vertical displacement,the maximum value is 0.05 mm,although the value is not large,but the change of stress redistribution is great,so it should do a good job in the construction process.As the distance between the excavator and the pipeline gradually increases,the deformation of each part of the pipeline has no obvious change trend.The reason is that the excavation period of the pipeline foundation pit is short and the static load of the excavator is short,so it has no obvious influence on the pipeline.The influence of vehicle load on pipeline with and without box culvert protection is analyzed numerically.When the pipeline is not supported,the maximum stress position in the Z direction of the pipeline is in the middle of the pipeline,and the maximum stress value is 135 kpa.Due to the double influence of upper traffic load on soil and upper traffic load on pipeline deformation,the pipeline stress increases.Under the restriction of support,the stress in the Z direction of the pipeline itself is distributed to the support of the pipeline,which greatly reduces the internal force of the pipeline.The maximum stress value in the Z direction of the pipeline is 40 kpa,indicating that the internal force of the pipeline is obviously reduced under the action of culvert support,and the effect is remarkable.An experimental system for pipeline leakage monitoring and location was designed and built.The leakage experiments were carried out on the experimental system under different leakage point distance,inlet pressure and leakage hole aperture.The attenuation law of negative pressure wave was obtained.The larger the inlet pressure is or the larger the leakage hole is,the larger the negative pressure wave pressure is.