Velocity–Moisture Relationships for Sandy Soils: Experimental Results and Data Analysis

Many techniques have been proposed in recent years for in situ soil characterization, and among them, acoustic methods have been revealed to be particularly promising. These methods are based on measurements of the propagation velocities of seismic, sonic, and ultrasonic waves. However, in granular and porous mediums, velocities depend on the state of the saturation of the soil in a complex and not yet fully understood way. In this paper, a refined mathematical model to account for the effects of many soil properties such as porosity, bulk modulus, and pressure on acoustic wave velocity is proposed and investigated. The model has been validated by an experimental comparison between the measured and calculated values of velocities, using a kind of sand of known characteristics. A custom measurement system has been developed and realized for this purpose. The proposed model has potential applications in various areas, including geothermal resource evaluation, petroleum exploration, environmental protection, and archaeological and cultural site protection.