Cracking the Nuclear Code: Finding an Alternative to the Nuclear Density Gauge

Abstract

Two of the most basic quality control tests made in the field during soil construction are the soil's moisture content and density. The establishment of a uniform procedure to compare the performance of soil based on moisture and density began with E.E. Proctor in the early 1930s during highway construction in California. He found that, by simply measuring these two properties, he could determine if a soil was too dry, too wet, or too lose to perform at its peak capacity for load bearing. Later research showed that knowledge of just these two physical properties can provide further insight into the soil's stability, strength, and fabric, allowing prediction of its future behavior under changes in load and environment. Even better, in practice, determining these two physical properties in the field has become of the simplest tests to conduct, thanks to one unique device: the nuclear density gauge.The technical expertise that is now part of geotechnical engineering was of paramount importance in the ancient worlds. This is because before, but also after, the invention of siege equipment, nearly all available defending or attacking techniques involved the excavation, transportation, and/or placement of soils or rocks to construct fortification walls and towers, excavate trenches and tunnels, or construct ramps, levees, and embankments. Although military geotechnics expertise in the ancient world was purely empirical, numerous case histories demonstrate the defining role that experienced engineers played in the outcome of military expeditions. This article highlights some characteristic examples of the role of military geotechnics in the ancient world.