Frequency-dependent attenuation of soils in seismic simulation
A seismic simulation is performed on a synthetic soil-rock model with frequencydependent attenuation spectra of soils. A detailed attenuation (i.e., quality factor, Q) characterization of remolded kaolin is obtained by utilizing a newly developed non-resonance experimental method. The attenuation spectra exhibit an apparent and consistent hump-shape frequency-dependent pattern in the seismic frequency range and demonstrate general and quantitative similarity to previously studied natural soils of different geologic origins. This frequencydependent attenuation behavior cannot be described with the simplified linear relationships with respect to frequency for modeling applications. A frequencydependent attenuation spectrum of soils is established in a polynomial formula in the frequency range of 10 -2 to 30 Hz. To quantify the frequency-dependent effect on the amplification, a transfer function which is established for vertically propagating SH waves passing through a single soil layer underlain by bedrock is used. The results from the simulation indicate that the accurate characterization of frequency-dependent attenuation is instrumental in amplification spectra estimate; whereas constant Q assumption may overestimate the amplification spectra at a maximum of 7 times at 30 Hz for SH waves traveling through a soil layer of 100 m thick.
|Conference||8th US National Conference on Earthquake Engineering 2006|
Meng, J. (Jiewu), & Motazedian, D. (2006). Frequency-dependent attenuation of soils in seismic simulation. Presented at the 8th US National Conference on Earthquake Engineering 2006.