Nonlinear Amplification of Seismic Ground Motion by Twin Cavities

This paper presents nonlinear amplification of seismic ground motion by twin cavities in layered sites. The equivalent linear method is used in the dynamic analysis and Lysmer-Kuhlemeyer transmitting boundary is used at the left and right boundaries of the computation region. It is shown that, cavities have significant effect on seismic ground motion, and soil nonlinearity has significant effect on seismic ground motion around cavities. The PGAs in linear and nonlinear analysis may be increased by 24.4% and 19.2%, compared with those in the free-field response. The PGA in nonlinear analysis may be decreased by 44.6%, compared with that in the linear analysis.