| Abstract: | A numerical model for wave scattering problems due to P and SV wave incidences is outlined in this paper. After verifying the present model, a general parametric study on the displacement patterns along the canyons of different shapes due to P and SV wave incidences is also performed. In order to investigate the effects of geologic conditions on ground motions, a weathered V-shaped canyon, which has different elastic moduli in the weathered layer, is also considered herein. The numerical results from this investigation demonstrated that (1) the present model is very suitable to simulate the problem of P and SV wave scattering along a natural canyon; (2) the shape of a canyon may have important effects on the displacement patterns along the canyon, so that a rectangular canyon is not appropriate to be a dam site due to its high amplification effects on incident waves; (3) the weathered layer on the surface of a canyon will significantly amplify the free field motion, especially for the case of softer weathered layer. Therefore, the excavation or grouting on a dam or a bridge abutment is not only necessary for static stability under static loads, but also beneficial to earthquake resistance because less amplification can be expected for sound rock abutments. |
