Study On Safety Of Buried Gas Pipeline Under Rockfall Impact

With the advancement of urbanization,the area of buried gas pipeline network continues to expand.In mountainous cities such as Chongqing,buried pipelines may be affected by disasters such as collapse and rockfall.The impact of rockfall on buried pipelines may cause them to deform or even rupture,causing Pipeline leak accident.In order to ensure the safe and stable operation of buried gas pipelines,this paper carried out a research on the safety of buried gas pipelines under the impact of rockfall,analyzed the stress state of the pipeline under the impact of rockfall,and studied the radius of rockfall and impact velocity of rockfall by finite element method.The influence law of factors such as the buried depth of the buried polyethylene pipeline and the steel pipeline on the dynamic response of the buried polyethylene pipeline and the steel pipeline,the safety of the buried gas pipeline under the impact of rockfall was analyzed by the limited state equation of the pipeline,and the rockfall protection of the buried gas pipeline was proposed.measures and analyze their effectiveness.The research results can provide theoretical guidance for the safe operation of buried gas pipelines in areas where rockfall may occur.The main research contents of this paper are as follows:1.Analyze the calculation method of rockfall impact,the transmission of impact load in the soil,and the axial and lateral forces of the pipeline under the action of rockfall impact.Combine the stress state of the pipeline and the mechanical properties of the pipeline material to clarify the impact of rockfall Failure criteria for buried PE pipes and steel pipes.2.Based on the explicit dynamics module of the ABAQUS software,establish a threedimensional dynamic response analysis model of the buried PE pipeline impacted by rockfall and the steel pipeline considering the external anti-corrosion layer,and analyze the dynamic response law of the buried pipeline under the impact of rockfall.With the increase of radius and impact velocity,the maximum Mises stress of PE pipeline,steel pipeline and outer anti-corrosion layer showed a significant increase trend.With the increase of pipeline burial depth and wall thickness,the stress of pipeline gradually decreased.3.Based on the dynamic response law of the pipeline under the impact of rockfall,the orthogonal test designs and variance analysis of the buried pipeline were carried out by using SPSS software,and the significant influencing factors on the maximum Mises stress of the pipeline were determined,and then the method of multiple regression analysis was used to establish The multi-factor limit state equation of the buried gas pipeline under the impact of rockfall is developed to analyze the safety state of the pipeline.4.Under the same rockfall impact,the safety of steel pipelines is higher than that of PE pipelines.Increasing the buried depth of the pipeline can significantly improve the safety of buried pipelines under the impact of rockfalls.When the actual situation cannot meet the requirements of buried depth,EPS cushion can be added above the pipeline to improve the safety of the pipeline under the impact of rockfall...