Evaluation of Soil State Variation using Bender Elements Within Centrifuge Models

Abstract

In centrifuge modelling, in-flight soil conditions can vary horizontally depending on the location, i.e., from the center of model to a point close to the rigid wall. Moreover, loading history and earthquake shaking events affecting the particle contact force can influence the in-flight soil conditions. For reliable centrifuge modelling, therefore, it is important to evaluate the in-flight soil properties in a soil model at specific locations before target experiments are performed. A series of centrifuge model tests were undertaken on a uniform dry sand to investigate the in-flight soil parameters by measuring shear wave velocity (V-s) via bender elements (BE), as the V-s of the soil is directly related with soil properties. Three plausible conditions likely to influence the soil parameters were discussed in this paper: (i) boundary condition (location from the container boundary), (ii) load history (sequence of spinning up and down in the centrifuge), and (iii) earthquake shaking events. The V-s measured in the centrifuge was verified through comparison with resonant column (RC) test results. The results showed that the V-s is different in horizontal plane with locations within the model as well as with different loading events. The results also confirmed that the evaluation of in-flight soil properties before performing the test is important for interpreting the soil behavior accurately.