Wave Propagation in Soils: Multi-Mode, Wide-Band Testing in a Waveguide Device

This paper presents the development of a waveguide device and the corresponding processing methodology to study wave propagation in particulate materials. Its main advantages are: the cancellation of biasing transfer functions (e.g., transducer, coupling, and electronics); the determination of both velocity and attenuation in a wide frequency range; the evaluation of torsional, flexural, and longitudinal propagation modes; and the computation of field propagation parameters from laboratory multi-mode data. Fundamentals of signal processing are reviewed, followed by a discussion of design considerations including boundary effects and geometric dispersion. Typical results are presented.