Study nonlinear vibration characteristics of vibrating roller-subgrade coupled system in the initial and middle stages of vibratory compaction

The vibratory roller’s compaction in the initial and middle stages is crucial for transforming loose subgrade filler particles into a dense state. The subgrade shows nonlinear characteristics of large and small plastic deformation. To describe these nonlinear characteristics, a new nonlinear model of vibratory roller-soil coupling is proposed. Initially, a two-degree-of-freedom model of the vibrating roller-subgrade system is established, considering the subgrade’s vibration. A small parameter is introduced to improve the elastic element of the frame shock absorber and the subgrade’s nonlinear hysteresis model. The analytical solution of the proposed nonlinear dynamic equation is solved and verified by the numerical solution. Subsequently, the vibrating wheel’s nonlinear dynamic responses are studied, including time-frequency domain, Poincare section, and bifurcation diagrams. It is found that during the initial stage, increasing excitation frequency or decreasing excitation force causes the vibrating wheel’s response to shift from “double period” to “single period.” In the middle stage, the vibrating wheel’s motion exhibits three states: “chaos,” “double period,” and “single period.” These nonlinear vibration response characteristics provide a theoretical foundation for selecting intelligent compaction parameters.