Strength property estimation for dry, cohesionless soils using the military cone penetrometer

Abstract : The US Army Engineer Waterways Experiment Station (WES) has successfully used cone index (CI) values obtained from the Military Cone Penetrometer Test to characterize soil strength since the 1950's. Over the past 40 years, WES has accumulated a large database of CI values throughout the world. These CI values have been used in empirical vehicle-soil interaction relationships to predict vehicle performance. These empirical relationships are rapidly being replaced by more theoretical models that rely on Newtonian physics and complicated track-soil and tire-soil interaction models to predict vehicle performance. The newer, more theoretical models require that the soil be characterized by fundamental engineering properties such as friction angle, shear modulus, and unit weight rather than simple index properties. In order to make use of existing and future bodies of CI data worldwide, relationships must be developed for translating CI values into fundamental engineering properties. As a starting point, a simple system has been developed for estimating the unit weight, friction angle, and shear modulus of dry, cohesionless soils based solely on their Unified Soil Classification System soil classification and CI values obtained in the field. That system is detailed in this report and a limited amount of available validation data is presented.