Determination of the variable contact geometry between a vibrating drum and the soil surface from measurements

Abstract

The paper presents a geometric model for the determination of the variable contact geometry between the drum of a vibratory roller and the soil surface from measurements. The main non-linearities of the dynamic roller-soil interaction 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 behavior of the drum at the same time. Moreover, a periodic loss of contact between drum and soil during the unloading phase usually occurs, 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 calculation of the variable contact geometry based on horizontal and vertical accelerations, measured in the bearing of the vibrating drum. The model is tested on measurements conducted with a typical single-drum roller. 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.