Consideration of the variable contact geometry between the drum and the soil surface in vibratory roller compaction

Abstract

The paper presents a comparatively simple mechanical model, which describes the dynamic interaction between the drum of a vibratory roller and the underlying soil during compaction. The main non-linearities of the dynamic system are the continuously varying contact conditions and geometry between the drum and the subgrade as well as the curved drum geometry. As the drum penetrates the soil during the loading phase, the contact area between the two contact partners increases, which in turn affects the resulting soil reaction force and influences the motion behaviour of the drum at the same time. Moreover, a periodic loss of contact between drum and soil during the unloading phase may occur, and the two subsystems move separately and independently from each other for a short period of time. The model introduced in the paper allows for a consideration of the challenging contact conditions and the variable drum contact geometry. Moreover, it enables the consideration of varying soil resistance as a result of the changing contact conditions. The model is tested on the example of a typical vibratory roller and the results are compared to a simulation with a constant contact geometry between drum and soil. The presented findings allow for a more accurate consideration of the actual contact conditions between the drum of a vibratory roller and the soil and are considered valuable for the further development of measurement values of Intelligent Compaction.