Investigation into the influence of vibratory roller dynamic characteristics on interaction features of Frame-Drum-Soil system elements

Introduction. Vibratory rollers are widely used for soil compaction in various types of construction. The technological efficiency of vibratory rollers depends on their technical characteristics, including the frequency and driving force of vibrations, as well as the properties of the soil.Materials and methods. To study the interaction of the elements of the Frame–Drum–Soil system, a three-mass rheological model has been developed that makes it possible to study the detachable and continuous modes of oscillation of the roller. Taking into account the deformability of the drum made it possible to form a more general rheological model applicable not only to smooth-wheel vibratory rollers, but also to vibratory rollers with hydrospring, pneumatic, rubberized and other designs of deformable drums.Results. According to the developed rheological model, a computational experiment was conducted for the DM-614 vibratory roller. The values of the maximum contact force Fсmax transmitted by the roller to the ground are usually less than the value of the driving force P. With an increase in the value of the driving force P and the coefficient of elastic resistance of the soil ks, the value of Fсmax increases slightly. As the oscillation frequency increases, the vertical oscillation range of the roller and its frame decreases, as well as the values of Fсmax over the entire range of permissible values of ks. Due to the violation of the symmetry of the contact force waveform during the transition from the "constant contact" mode to the "partial separation" mode, with an increase in the oscillation frequency, instead of the expected decrease in the loading time tн and unloading time tp, their increase is observed with certain combinations of the driving force P, the oscillation frequency f and the soil properties ks. Therefore, when compacting the soil in the final stage (at high values of ks), it is advisable to increase the oscillation frequency not only to prevent the transition to an undesirable "double jump" mode, but also to increase the duration of contact stresses, which determines the depth of their propagation and the depth of the soil compaction zone.Discussion and conclusion. The results of the study make it possible to obtain not only a qualitative description of the impact of the main dynamic characteristics of a vibratory roller on its technological efficiency, dynamic loads on structural elements and vibration safety, but also to quantify these indicators. The analysis showed that when designing new and upgrading existing vibratory rollers, it is necessary to take into account the implemented oscillation mode, which was not previously taken into account in the practice of domestic road construction engineering.