Abstract: There are phenomena of cut-off or truncation for Rayleigh wave dispersion curves when transfer matrix approach is used to calculate dispersion curves of some irregular horizontal layered profiles. But these can be avoided if the appendant layer method is adopted. In order to study the validity of this new method, phase velocities and the excited intensities are compared before and after appendant layer method used. The author calculates dispersion curves and the change of displacement components with the depth of three irregular profiles by the appendant layer method. According to the calculating results and comparative analysis, the appendant layer method can calculate not only the guided waves, but also the leaky mode waves. At a fixed frequency point, the error of the excited intensity between modified and original models decreases with the appendant layer’s burying depth increasing. And for an invariable burying depth of the appendant layer, the error is decreases with the frequency increasing. It is obvious that Rayleigh wave dispersion curves of some irregular profiles can be calculated by the appendant layer method on the basis of practical accuracy demand.

Key words: Rayleigh waves, appendant layer method, guided wave mode, leaky mode