Propagation characteristics of low-frequency axisymmetric waves in fluid-filled pipes embedded in the viscoelastic medium

This study devotes to investigate the propagation characteristics of low-frequency axisymmetric waves in buried fluid-filled pipes.The surrounding soil is regarded as the viscoelastic medium.The Kennard thin-walled shell equations are combined with the Kelvin-Voigt linear viscoelastic model,and the soil loading matrix is introduced to derive the expressions of the phase velocity for both the fluid-dominated wave and the shell-compressed wave under the state of pipe sliding contact with soil.The dispersion and attenuation curves of the fluid-dominated wave and the shellcompressed wave are obtained by numerical simulation,and the reliability is verified.The ratio of the radial pipe wall displacements associated with the two waves is analyzed,-the effects of the thickness-to-radius ratio and the quality factor on the fluid-dominated wave are discussed.The results show that the viscoelastic medium has little impacts on the phase velocities of the fluid-dominated wave and the shell-compressed wave,but has great impacts on the attenuation;the fluid-dominated wave effects the radial displacement of pipe wall greatly and is responsible for the propagation of leakage noise;the phase velocity of the fluid-dominated wave increases and the attenuation decreases with the thickness-to-radius ratio;the dispersion and attenuation of the fluid-dominated wave decrease with the quality factor.The research results can provide some theoretical instruction and guidance for leakage detection of buried fluid-filled pipes.