Analysis Of Dynamic Response Of Buried Pipeline Under Multi-Point Seismic Wave Input

The research on the seismic analysis method of long span pipeline is still a common concern at home and abroad.Long distance buried pipeline may occur large deformation and damage.At present, there are many researches, but the input method is the consistent excitation method.For the span is not very long pipeline, this type is acceptable. The measured seismic data show that the amplitude and frequency at different points are different due to the influence of traveling wave effect, partial correlation effect and local site effect. Therefore, for the long span pipeline, considering the correlation of the vibration, the multi-point seismic input method is more realistic.This paper uses a kind of infinite elastic foundation beam deformation curve as vibration curve, and can completely satisfy the boundary conditions of the problem, then according to the structural dynamics calculatiting dynamic formula, then Matlab is used to calculate the long span of buried pipelines.The calculation results show that the displacement amplitude is increased under the same seismic excitation and multi- point excitation, but there is no obvious time lag.Bending stiffness coefficient of the cross section, subgrade modulus, damping coefficient,seismic wave travel speed, ground vibration frequency have certain influence, in the general field of characteristic frequency consistent input conditions, and the dynamic response value is increased by about 10%.Among them, bending stiffness coefficient of the cross section, pipeline mass per unit length, subgrade modulus of elasticity, damping coefficient, differences are smaller, change trend are also the same. Only the elastic characteristic length and the velocity of seismic wave have different effects. When the elastic characteristic length value is small, that is, the soil is soft, multi-point input has lower value, because the general setting of the site is not particularly soft subgrade soil,the seismic wave traveling wave(shear wave velocity) is greater than 150 m / s above,then the results under multi-point input is greater, in the design and calculation of buried pipelines should be included. Therefore, the multi-point ground motion input should be considered in the calculation of seismic design of the long span pipeline.