An Analytical Calculation Method and Mechanical Response Laws of Buried Pipelines Subjected to the Impact of Transverse Landslides

When the buried gathering and transportation pipelines cross the landslide area transversally, the migration of the landslide mass can cause the pipelines to be subjected to lateral thrust, which can seriously affect the safe operation of the buried pipelines. In order to study the mechanical response laws of the buried pipelines under the impact of transverse landslides, based on the elastic-plastic foundation beam theory, the mechanical models of buried pipelines are established for three situations, and the analytical solution of pipeline displacement is obtained by genetic algorithm. The influences of landslide thrust, landslide width, soil resistance coefficient, the pipe outer diameter and wall thickness on pipeline peak displacement and peak stress are also investigated. The results show that under the impact of the transverse landslide, with the increase of landslide thrust, the maximum displacement and maximum tensile stress of pipeline increase exponentially, and the failure risk of pipe increases. Secondly, with the increase of landslide width, the maximum displacement of pipeline increases in the beginning and then decreases to be constant, and the maximum tensile stress decreases sharply to be constant. Thirdly, with the increase of soil resistance coefficient, the maximum displacement and maximum tensile stress of pipeline decrease in a negative power trend, and the pipeline is safer. Fourthly, when the pipe outer diameter increases to a certain value, the maximum displacement and maximum tensile stress of the pipeline change very little, hence, pipe outer diameter can be optimized when designing pipe structure. Fifthly, the smaller the pipe wall thickness is, the greater the maximum tensile stress of the pipe is, therefore, pipe corrosion protection should be paid attention to. Sixthly, when the landslide thrust is large, the landslide width is small, or the pipeline outer diameter is small, the maximum tensile stress of the pipeline is located at the centre of the landslide, otherwise, it is located at 0.56L ~ 0.7L away from the landslide centre. In order to ensure the safe operation of the pipeline, the stress state of these two positions should be focused on. It is concluded that the study can provide the basis for the evaluation of pipeline safety status and has practical significance for ensuring the safe operation of buried pipelines.