Rational equipment selection method based on soil conditions

This paper presents a rational approach for evaluating a tractor dozer's capability to excavate a given soil type. A number of empirical charts exist for equipment selection, and a complex formulation based on soil mechanics theory can be applied to predict dislodgement forces. However, there is no current method to compute dislodgement forces based on soil properties and uses the results as a basis for equipment selection. This paper proposes a simplified model based on Coulomb lateral earth pressure theory to predict dislodgement forces for a dozer blade geometry. The results from the simplified model analyses are verified using the more complex existing theory. Based on the results, a set of practical decision charts are developed that can be used by the practitioner to estimate the tractor dozer's ability to excavate various types of soils. I provide an example of how the charts are used to select equipment given a set of natural soil conditions. The methodology proposed, if verified in field tests, could be used to develop a comprehensive series of charts for various equipment models and soil types.