Search

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 executed. A test method, similar to the sand-cone method, was developed that uses steel shot as the material to which a volume 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. Excavated 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.

The focus of this work was to evaluate the use of commercially available matting systems to sustain C-130 and C-17 transport aircraft loads over soil bases having different California bearing ratio (CBR) ranges. Test sections were constructed using three range of CBR: high (CBR=40–50), medium (CBR=8–10), and low (CBR=5–6). Testing began with the C-130 load cart and six different matting systems. The C-130 was the lesser of the two aircraft loads examined and this initial testing was used as an "elimination round" for the various matting systems chosen. Matting systems deemed suitable for the C-130 were further tested under the C-17 load cart. Systems were evaluated based on logistical and assembly requirements, mat damage sustained during traffic, and accumulated deformation of the mats and soil during traffic. The latter are shown in line plots of passes versus plastic rut formation. Summary information on each matting system tested and the test sections themselves is presented. Conclusions on the matting systems tested and their application are discussed.