Research On The Dynamic Response Of Multilayered Elastic And Saturated Poroviscoelastic Media

The common method for obtaining the dynamic response of multilayeredfoundation was proposed by Thomson and Haskell. The method would yield a poorlyconditioned numerical system due to the presence of mismatched exponential terms.This paper employs the generalized transfer matrix method for investigating wavepropagation in both layered elastic media and poroviscoelastic media. The generalizedtransfer matrix divides the transfer matrix, forming both upgoing and downgoing wavesubmatrices, and then introduces auxiliary interfacial matrixes. Consequently,increasing exponential terms only remain. The general relationship between thedisplacements and stresses of the multilayered media is obtained in frequencywavenumber domain. With an interfacial stiffness matrix introduced, the generalizedtransfer matrix method yields the dynamic stiffness matrix realting the displacement tostress of the surface. An adaptive integration method for the inverse Fourier transformgets the dynamic coefficient in frequency domain, and then the dynamic stiffnessmatrices of the layered media and the rigid footing bonded to the layered. The integrandis expressed with Chebyshev expansion. According to different conditions, eithor therecursion formula or the Taylor expansion is taken. This method can adjust integratinginterval with irregularly oscillatory integrand, resulting in a more efficient and accuratescheme than other commonly used methods. Moreover, the numerical results from thewave propagtion in poroviscoelastic media can not be represented in a dimensionlessmanner. Therefore, the corresponding dimensionless results are only given withoutdamping.The generalized transfer matrix method has many advantages over other availablecomplex arithmetic methods. Firstly, it keeps the simplicity of the original method butnaturally excludes the exponential decrease terms. So the stability of this method is thesame as those of the global matrix method. Secondly, in the derivation process, we cansee the inhomogeneity of the layered half-space can be ignored with the increasingfrequency or layer thickness. Finally, due to its concise submatrix form, the generalizedtransfer matrix method is the most efficient of all the complex arithmetic methodsavailable, including the original Thomson-Haskell method.