Compressional and shear wave intrinsic attenuation and velocity in partially saturated soils

• A model for propagation of waves in partially saturated soils is presented.
• The model considers the tortuosity of fluid phases which are dependent on suction.
• Closed-form dispersion relations are found for compressional and shear waves.
• Numerical simulations are performed on sand saturated with air–water mixture.
• The effect of frequency and saturation on wave velocity and attenuation is studied.

A model for studying the propagation of compressional and shear waves in partially saturated soils is presented. The pores are filled with two immiscible fluids and the existence of four different wave modes including three compressional waves and one shear wave is demonstrated. The novel feature of the model is the consideration of tortuosity of fluid phases which are dependent on matric suction. The dispersion relations derived from the presented model are incorporated to study the influence of fluid saturation degree and frequency on the velocity and intrinsic attenuation of shear and compressional waves. Numerical simulations are performed on sand containing air–water mixture.