DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click HERE
to register or log in.
Acoustic Determination of Near-Surface Soil Properties
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
Pagination or Media Count:
The state of the ground can change dramatically in response to changing meteorological influences and physical disturbances of the ground e.g. tilling that are important to many civilian and military activities. Permeability is the fundamental parameter of a porous media that controls whether a surface is an acoustically hard one, through which fluids may not easily penetrate, or conversely a more transparent surface, across which gas and water may readily move. Permeability is the property that controls pressure-driven processes including rain infiltration in soils, surface-atmosphere gas exchange, and acoustic response of the ground. In this paper we describe results of preliminary field tests of the acoustic response of a sand surface under several conditions of moisture and disturbance. We compare these measurements to results of our theory by which a point acoustic source can be used to remotely determine the soil permeability on scales from centimeters to tens of meters across the ground surface. In addition to acoustic means of determining the permeability, we also make a number of direct, co-registered measurements of permeability for comparison.
APPROVED FOR PUBLIC RELEASE