Lillian D. Wakeley

Steel-shot method for measuring the density of soils

The density of soil is crucial in engineering, construction, and research. Standard methods to determine density use procedures, equipment or expendable materials that limit their effectiveness in challenging field conditions. Some methods require burdensome logistics or have time requirements that limit their use or the number of tests that can be exe- cuted. A test method, similar to the sand-cone method, was developed that uses steel shot as the material to which a vol- ume of soil is compared to calculate soil density. Steel shot is easily recovered and reused, eliminating the need for specialty sand and calibrated cones or containers, and allows rapid determination of the volume of displaced soil. Exca- vated soil also provides measurements of total mass and moisture content. Volume, mass, and moisture content are applied in simple calculations to determine wet and dry densities and unit weight of the soil. Proficiency in performing the test can be achieved with minimal training, and the required kit can be assembled for a reasonable cost. Field uses of the method in dry environments in a variety of soil types demonstrated that the method can produce repeatable results within 2% of the values of soil density determined by traditional methods, with advantages in logistics.

Geophysical Analysis of the Upper Six Meters of Soil, East‐Central Dugway Proving Ground, in Support of Military and Homeland Security Interests

October 2010 field investigations in the east-central part of Dugway Proving Ground included geophysical investigations coupled with extensive soil sampling and field investigations of stratigraphy in support of military and homeland security interests.

Development of an integrated soils laboratory for modeling and detection applications

The Geotechnical and Structures Laboratory at the US Army Corps of Engineers, Engineer Research and Development Center (ERDC) has developed a near-surface properties laboratory to provide complete characterization of soil. Data from this laboratory is being incorporated into a comprehensive database, to enhance military force projection and protection by providing physical properties for modelers and designers of imaging and detection systems. The database will allow cross-referencing of mineralogical, electromagnetic, thermal, and optical properties to predict surface and subsurface conditions. We present an example data set from recent collection efforts including FTIR in the Near-IR, MWIR, and LWIR bands, magnetic susceptibility (500 Hz to 8 GHz), and soil conductivity and complex permittivity (10 μHz to 8 GHz) measurements. X-ray data is presented along with a discussion of site geology, sample collection and preparation methods, and mineralogy. This type of data-collection effort provides useful constraint information of soil properties for use in modeling and target detection. By establishing real ranges for critical soil properties, we are able to improve algorithms to define anomalies that can indicate the presence of land mines, unexploded ordnance (UXOs), improvised explosive devices (IEDs), tunnels, and other visually obscured threats.