Soil characterization in centrifuge models through measurement of shear wave velocities using bender elements

The determination of the dynamic properties of the soil is a critical issue in geotechnical engineering. It is of a particular importance in problems involving dynamic excitation of soil systems, such as earthquakes. This research focuses on measuring the velocity of seismic waves, particularly shear waves, in the centrifuge soil models. The high noise during the centrifuge operation, and the need of using a number of bender elements in the same model, makes the use of bender elements in the centrifuge more challenging. The research starts with improving the current bender elements system at RPI Geotechnical Centrifuge Center. This involves solving electric and electromagnetic problems in the system and reducing noise and ghosting effects. The improved bender elements system is then used to determine the shear (S) wave velocities of dry Ottawa sand at different void ratios and different overconsolidation ratios in the centrifuge. The shear wave velocity measurements are also used to estimate the effect of overconsolidation on the coefficient of lateral earth pressure at rest (Ko). A comparison of the results is done with those published in the literature.