Abstract
To explore the control indexes of coarse-grained chlorine saline soils used as subgrade fillings, a series of indoor dynamic triaxial tests and CBR tests are conducted. And then the evolution law of the dynamic rebound modulus and CBR of coarse-grained chloride saline soils is analyzed under the conditions of different stress levels, water content, and salt content. The experimental results show that the dynamic rebound modulus increases with the increase of confining pressure and body stress, and decreases with the increase of deviatoric stress. The CBR increases with the increase of unit pressure. At the same level of stress, the higher the salt content and water content, the more significant the effect of stress on the dynamic rebound modulus and CBR, and the salt content has a more significant impact than that of water content. The maximum reduction amplitudes in the dynamic rebound modulus are 43.3% and 13.5% corresponding to salt content and water content, respectively. The maximum reduction amplitudes in the CBR are 65.9% and 51.4%, respectively. Finally, based on the experimental data, a prediction model of the road performance index is proposed and the salt content threshold values of coarse-grained chloride saline soils used as subgrade fillings are calculated at different depths. The results of the study provide a solid support for the use of coarse-grained chloride saline soils as subgrade fillings.