Abstract: The performance evolution of subgrade soil under the coupling effect of drying?wetting cycle and dynamic load is essential for the safety and stability of the subgrade. In this study, a series of electrical resistivity tests was carried out on the compacted silty clay samples subjected to different drying?wetting cycles and dynamic loads using alternating current (AC) two-electrode method. The effect of drying?wetting cycles sequentially coupled with dynamic loads on the electrical resistivity of soil samples was investigated. Then, a mathematical relationship was established to quantitatively characterize the dynamic behaviors of soil samples based on electrical resistivity. Finally, the effectiveness of the electrical resistivity method in evaluating the state of compacted soil was discussed. Test results showed that under the action of drying?wetting cycles coupled with dynamic loads, the electrical resistivity of soil samples decreased greatly with the increases in the number and amplitude of drying?wetting cycles, but the reduction of the electrical resistivity of soil samples caused by dynamic load decreased gradually. The test results can provide a reference for the evaluation of the state of subgrade soil under drying?wetting cycles sequentially coupled with dynamic loads using electrical resistivity method.

Key words: electrical resistivity, drying?wetting cycle, dynamic load, sequential coupling effect, subgrade soil