Security Analysis On Buried Pipelines In Seasonal Frozen Area

Because surrounding environment of long distance pipeline is very complex and geographical conditions are various,all kinds of geological disaster area will inevitably be encountered in the process of laying and operation by pipeline.The serious threat will been posed to the pipeline of the long-term safe operation in these disaster area.In this paper,the mechanical properties of buried pipelines under the frost heave were studied,and the influences of the complex loads under the combined action of earthquake and frost heave on the normal operation of buried pipelines were studied.The main research contents and results were approved as following.1)In order to know the changes of structure force characteristics in time during the pipeline operation,the basic solution of "mechanics of materials" of Timoshenko in the beam on elastic foundation was used,and the analysis of buried pipeline in soil solution under the condition of uneven frost was got.2)Based on the literature review and theoretical research,the three-dimensional temperature field model of pipe soil was established,the distribution of temperature field was simulated,and the temperature was compared with the measured ground temperature in the records by using the finite element software ADINA.3)Established three-dimensional pipe-solid structure model by using the finite element software ADINA,thermo-mechanical coupling analysis of buried pipeline was done,calculated the frost heaving force of pipeline after solid frozen,analyzed the influencing factors were temperature,the depth of buried pipeline,transition segment length,internal pressure of pipeline,the length of frost heaving segment,determined the location of largest stress in pipeline.4)Adding the earthquake on the solid with frost heaving,analyzed influence of buried pipeline structure by the complex loading which made by earthquake and solid frost heaving,analyzed the influence by temperature,the depth of buried pipeline,transition segment length,internal pressure of pipeline,the length of frost heaving segment,provided some advises for the researched of buried pipeline under complex loading.