Centrifuge and numerical modelling of ground-borne vibration from surface sources

Abstract

For the study of ground-borne vibration from surface sources, it is commonly assumed that soil properties remain constant with depth. However, various studies in the field of geotechnical engineering have shown that soil properties (stiffness and damping) change with depth due to the effect of increasing confining stress. Ground-borne vibration is hence unrealistically simulated if constant soil properties are assumed throughout a half space or a soil layer. This paper presents a study of the effect of the variation of soil properties with depth, referred to as soil non-homogeneity, on ground-borne vibrations induced by surface sources. The study involved physical modelling using a geotechnical centrifuge and numerical modelling using EDT and FLAC to gain further understanding of experimental results. In the centrifuge model, a dynamic excitation was applied to a rigid foundation resting on the surface of sand within a cylindrical container. Dynamic soil response was measured using accelerometers on the surface and within the soil. Comparison of the experimental and numerical results demonstrated that it is important to account for the variation of soil properties with depth when studying ground-borne vibration from surface sources.