Trafficability of Fine-Textured Arid Soils – a Model Evaluation

Terramechanics of fine-textured desert soils is of increasing interest for civil and military off-road vehicle operation as well as soil protection and remediation activities. Fine-textured arid soils are characterized by their high porosity and pronounced secondary structure (e.g. vesicular A-horizons), formed in the course of time due to aggregation or segregation of primary soil particles to aggregates or peds. This secondary soil structure deteriorates when subjected to intensive or repetitive vehicle traffic resulting in a lunar dust like material of decreased stiffness and strength compared to the undisturbed soil. The subsequent increase in vehicle sinkage and dust emission and decrease in vehicle traction, lead to decreasing trafficability and visibility as well as negative environmental impacts like fast and deep soil erosion. The goal of this study is to investigate the process of soil structure deterioration due to heavy vehicle traffic and the influence of structure loss on soil trafficability. In a first step, we evaluated available terramechanics models, developed to predict trafficability of humid and cold-area soils, when applied to fine-textured desert soils using data from traffic experiments with a variety of wheeled and tracked vehicles at the Yuma Proving Ground.