Analytical Solutions For Scattering Of Rayleigh Waves By Alluvial Valleys

Scattering and diffraction of earthquake waves by alluvial fields can affect theground motion and architectures nearby on the ground. Therefore, it is important tosolve the problem in theory and in engineering application. Analytical solutions for the scattering of alluvial valleys subjected to the incidentplane Rayleigh waves were derived in the thesis by the Fourier-Bessel seriesexpansion technique. Three conditions in regard to the alluvial field from simple tocomplex were considered:the simple alluvial field, the layered alluvial valley and thealluvial canyon. The accuracy and convergency of the solution are tested, too. Themethod of wave function expansion was adopted. The potential functions in free fieldwere derivated firstly, then they were expanded on the corresponding boundary by theFourier-Bessel series expansion technique. Results show that such factors affect the ground motion to different extent as thethickness of the alluvial layer, the ratio of thickness and width, the sequence andstiffness of the alluvial layers and so on. It was shown that the alluvial layer amplifiesincident plane Rayleigh waves tremendously, and the amplification can be more thantwo times than that for a simple field without the alluvial layer;the stiffness andthickness of the alluvial layer also have great effects on the field dynamicalcharacteristic.