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

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