抄録
Scattering of harmonic waves by subsurface irregularities is studied experimentally with the detailed measurements of a surface ground motion generated by forced vibration of a reinforced concrete model footing placed on a subsurface irregular ground. Observations indicate that the variations of measured velocity amplitude are most influenced by SH wave motion among various types of propagating waves and that they are highly frequency dependent. They also indicate that the measured velocity amplitudes do not always decay monotonously with increasing the source-receiver distance and that it is the measurement points of the filling ground in the vicinity of interface between the cutting ground and filling ground that surface ground motions are significantly amplified. The variations of measured velocity amplitudes have been modeled by a two-dimensional model of an arbitrarily-shaped soil deposit excited by forced vibration of a footing and it is analyzed by the indirect boundary integral equation. It is shown that the computed amplitude variations coincide qualitatively with the observed ones.
