Theoretical And Numerical Investigation Of Static And Dynamic Behavior Of Surrounding Soil And Buried Pipeline

摘要

The effect of wave 'propagation produced by earthquake is a very significant factor that damages pipeline systems. When earthquake waves distribute from the source, some motions occurs on the ground with non harmonic movement. If a pipeline locates between two points of ground which is under the earthquake waves, because of phase delay, strains and curvature will be produced along the pipeline. On this paper we will study the interaction between buried pipeline and soil and we will study static and dynamic performance parameters of the pipeline and the soil surrounding it such as static stiffness, dynamic stiffness, damping, additional mass share of soil which take part with pipe's mass in dynamic performance. Static stiffness of Winkler model and other dynamic parameters such as damping of soil, pipeline system, dynamic stiffness and part of soil mass which take part in the vibration performance with pipe mass could be determined with suggested formulation and experimental model. Applying this model, relation of static and dynamic stiffness parameters of soil and pipeline system and some effective factors such as depth of pipe buried, thickness of pipe, density of soil, water absorption percentage, dominate and hysteric frequent is evaluated. Practically, pipeline would be covered in a special depth of soil and surrounding soil will produce stress to the soil which can be estimated by Mareston theory. Usually, pipeline is located in a trenched soil and then covered. The equilibrium equation of axial vibration of an element of pipeline can be derived neglecting the effect of additional mass of soil share or without neglecting it. Finally the share of each parameters described before is estimated as a conclusion.