Frequency dependency of elastic wave velocities: determination of wave dispersion in sand under K ₀ compression

Bender and extender elements are effective tools for measuring elastic wave velocities in soils, yet their application to quantify frequency-dependent dispersion, a critical property reflecting particulate media dynamics, remains methodologically challenging. As inherently dispersive particulate systems, soils exhibit wave velocity variations with frequency, encoded information of internal spatial and temporal scales governing micromechanical behavior. However, existing techniques struggle to characterize these dispersion properties experimentally. This study establishes an approach to determine the soil wave dispersion characteristics by bender/extender elements using frequency sweep excitations. We systematically compare time-domain and frequency-domain methodologies for quantifying wave dispersion in sandy soils under one-dimensional K 0 compression, assessing their reliability, efficiency, and applicability under controlled vertical stresses and saturation levels. The soil wave dispersion characteristic curves demonstrate frequency-dependent attenuation for measured phase velocities of V s and V p , stabilizing at high frequencies where dispersion diminishes. S-waves display narrower dispersion ranges than P-waves. Elevated vertical stress amplifies V s and V p magnitudes while broadening their dispersion ranges, whereas increased saturation suppresses dispersion. The study bridges critical gaps in experimental dispersion analysis, implying further practical frameworks that correlate wave dispersion, soil microstructure, and micromechanical analysis for refining geophysical models and optimizing nondestructive testing protocols in geotechnical engineering.