Dynamic Response of Semicircular Canyon to Incident Rayleigh Waves

In this paper, coupled time-frequency domain boundary element method has been employed to investigate dynamic response of ground surface subjected to Rayleigh waves. The model consisted of a semicircular canyon cut from a homogeneous, linear and elastic half space. The total response was determined by summing up the responses of free field and scattered waves. The free field and scattered wave solutions were calculated from closed form solution of propagated waves in the half space and boundary element method, respectively. To perform boundary element analysis, the surface irregularities were discretized by linear elements whose weak and strong singularities could be removed by, respectively, analytical and rigid body motion concepts. Then, the influence coefficient matrices of elastic semi-infinite domain with semicircular canyon were obtained using harmonic fundamental solutions for displacement and traction. The horizontal and vertical spectral amplitude of ground motion were shown as a function of dimensionless frequency which contains the properties of medium, incident wave and canyon geometry. Semicircular canyon subjected to Rayleigh waves having different wavelength were considered in the analyses. The response in the time-domain is obtained from the frequency-domain solution by using Fast Fourier Transform (FFT) technique. By comparing the displacement amplitude of points in front and at the back of the canyon, it was concluded that the semicircular canyon has blocking effect for surface incident Rayleigh waves

کلیدواژه ها:

Boundary element method ، Wave propagation ، Semicircular canyon ، Rayleigh wave