The Dynamic Behavior of a Network of Pipelines and Liquefaction of Soil Caused by the Earthquake Acceleration

Risk analysis pipelines in the quake as one of the most vital arteries in the current circumstances in the world is of special importance. in our everyday activities, used to underground structures such as pipes, tunnels, wells and so on for services such as transporting water, transportation, irrigation, drainage, sewage disposal, transporting oil and gas, carrying acid waste, industrial, household and so on. With regard to the huge investments structures, especially buried underground pipes, we need to study these constructs in response to the earthquake, is clearly felt. Pipelines used for transporting gas and other fluids, are widely distributed in all areas. These lines due to passing through the densely populated areas are always buried in the earth. Seismic behavior of these pipes as a result of the interaction between the soil and the pipe is different from the above-ground structures. The manner of modelling of the effects of soil liquefaction on the pipes in this thesis is that two shear springs and a normal spring is defined between soil and the pipe that in liquefaction mode minimize the friction shear strength.