Waves In Layered Half-space Research Articles

Efficient Reformulation of the Thomson-Haskell Method for Computation of Surface Waves in Layered Half-Space

This paper presents an efficient and effective scheme for reforming the original Thomson–Haskell transfer matrix method for the stable modeling of surface waves in a layered half-space. The proposed scheme splits the layer propagator matrix and then determines the interface stiffness instead of directly building the propagator matrix as the original Thomson–Haskell method does. For the Love wave, an explicit solution for the interface stiffness is obtained. The reformulation of the Thomson–Haskell method keeps the simplicity of the original method but naturally excludes its exponential growth terms. Hence, the modified Thomson–Haskell method is computationally stable for high frequency and increasing layer thickness. Moreover, both analytical and numerical results indicate the modified Thomson–Haskell method is the most efficient of all the complex arithmetic algorithms available, including the original Thomson–Haskell method and generated reflection and transmission matrix method. The computational speed of the modified Thomson–Haskell method rises by more than 15% for the Love and Rayleigh waves. Furthermore, a discussion of the effect of frequency and layer thickness on the phase velocity of Gutenberg Earth model indicates the modified Thomson–Haskell method is a powerful candidate for efficiently and effectively simulating surface waves in a layered half-space.

Analysis of in-plane waves in layered half-space by global-local finite element method : Oner, M; Dong, S B Soil Dynam Earthq EngngV7, N1, Jan 1988, P2–8

Analysis of in-plane waves in layered half-space by global-local finite element method : Oner, M; Dong, S B Soil Dynam Earthq EngngV7, N1, Jan 1988, P2–8

Analysis of in-plane waves in layered half-space by global-local finite element method

An efficient numerical method is presented for analysing in-plane waves in layered halfspace. The geometry considered is a layered soil with arbitrarily distributed properties underlain by an elastic ‘subgrade’ which extends to infinity. Two alternative subgrade models have been developed with respect to material properties: (a) a uniform subgrade where properties are constant, and (b) an inhomogeneous subgrade where elastic moduli vary with some arbitrary power of depth. Comparisons made for the uniform subgrade case indicate the efficiency of the new technique. Some results are also presented for the inhomogeneous subgrade case for which there is no analytical solution available.