Abstract: In order to investigate the dynamic characteristics of reinforced gravel soil under cyclic loading, the consolidated undrained dynamic triaxial tests were carried out on the reinforced gravel soil with different numbers of reinforcement layers and confining pressures. The effects of the number of reinforcement layers and confining pressure on the dynamic characteristics of reinforced gravel soil were studied, and the development mechanism of axial cumulative strain of reinforced gravel soil was further analyzed. The results show that when the number of reinforced layers increases, the axial cumulative strain decreases, the rebound modulus increases, and the influence of reinforcement gradually decreases; when the confining pressure is increased, the axial cumulative strain of the soil decreases, and the rebound modulus and the dynamic pore pressure increase accordingly. As the number of reinforced layers and the number of cycle increase, the hysteresis curve gradually approaches the stress axis, and the hysteresis loop area gradually decreases, and the energy consumption of the soil weakens. Based on the stability theory and the indirect influence band theory, the mechanism of the influence of reinforcement on the development of axial cumulative strain is revealed. An axial cumulative strain prediction model of reinforced gravel soil that accounts for the effect of number of reinforcement layers is established. The parameters ?, ?, ? are linear with the number of reinforcement layers, and the model can effectively predict the deformation of reinforced gravel subgrade under cyclic loading.

Key words: gravel soil, dynamic triaxial test, reinforced soil, dynamic characteristics, axial cumulative strain