Shaking table test on the topographic effect of a symmetrical V-shaped canyon under streamwise excitation

Abstract

The local irregular topographies can substantially affect the seismic wave propagation and induce amplification or de-amplification of ground motions. Current research on the canyon topography effects mainly employs analytical and numerical methods, lacking the support from test data. The shaking table test is conducted in this paper to investigate the amplification effect of a symmetrical V-shaped canyon under streamwise excitation. The model canyon has a characteristic size of 1.0 m and a weight of 18 t. The excitation frequency band covers 0.1–100 Hz. The ratio of the canyon's characteristic size to the incident wavelength (i.e., the standardized size of canyon) is increased to 1.0. The acceleration time histories and corresponding Fourier spectrums recorded at monitoring points on the canyon surface are consistent with the theoretical calculation results. It means that the mutual verification between the test study and the theoretical study of the canyon topographic effect is realized. The influences of the dominant frequency and amplitude of input wave on the PGA amplification factor are systematically discussed. The threshold value where the topographic effect appears is proposed, i.e., the standardized size of the canyon η ≥ 0.08. The shaking table test is expected to provide a benchmark for the verification of the analytical and numerical studies on the canyon topographic effect.