Centrifuge modeling of dynamic response of high fill slope by using generalized scaling law

The development of physical modeling for mega engineering prototypes requires sophisticated use of the capability of current centrifuge facilities. In this study, centrifuge model tests were performed to investigate the dynamic response of high fill slope by using generalized scaling law in an improved way. Firstly the two-stage generalized scaling law was partly re-organized by considering the separate similitude of dynamic strain for the virtual 1 g field, to solve the inherent problem of the scaling of soil strain when the derived prototype strain exceeded some important thresholds. Then a series of centrifuge model tests were conducted under different centrifugal accelerations to model a high fill slope with a prototype height of 100 m by the approach of “modeling of models”. Dynamic responses under sine waves with different amplitudes were monitored and the re-organized generalized scaling law was validated for nonlinear dynamic response with shear strain less than 1%. It was observed that site amplification of high fill slope was affected by both soil nonlinearity and soil strata non-uniformity, where soil nonlinearity led to smaller acceleration amplification under stronger excitation and soil strata non-uniformity contributed to the acceleration de-amplification and larger displacement amplification at the weak sublayer. The large dynamic displacement near the slope surface consequently contributes to the development of lateral cracks after strong shaking. Seismic response under earthquake motions revealed that high fill slope with inclined non-uniform strata was characterized by multiple vibration modes and lower fundamental frequency, which was more vulnerable to earthquake motions with abundant frequency components. This study provides a more physically meaningful use of the similitude of dynamic stress-strain relation in centrifuge modeling for large-scale geotechnical problems under dynamic loadings.