Soil mechanics deals primarily with static or quasi static cases, rather than with dynamic loadings. In depth studies of the various interactions of machine and soil have not developed results which could be termed universal. The problem with soil is that properties vary from place to place (over a wide range), and at a particular place, soil properties vary from day to day, depending on climate, weather, and topography.
The author discusses the nature of soil and kinds of analytical measurements needed, including the use of classification systems, development of standardized measurement conditions and techniques, correlating test results, validating models, and solving design problems, both vehicle and pavement.
Soil property measurements are essential in engineering applications of soil machine systems and there is a pressing need for the engineering community to get on with this task.