Abstract: As an essential parameter for evaluating subgrade performance and pavement design, the dynamic resilient modulus is complex and changeable due to the significant influence of the physical and mechanical state and external environment. An efficient and straightforward monitoring method is urgently needed. In this paper, a series of dynamic resilient modulus tests and shear wave velocity tests were conducted on thawed silty clay under different degrees of compactness, moisture contents, and freeze-thaw cycles. Dynamic resilient modulus, shear wave velocity, and their conversion relationship of thawed silty clay were obtained. The results show that the dynamic resilient modulus and shear wave velocity of silty clay are closely related to its physical state. Both decrease sharply with the increase of moisture content and freeze-thaw cycles, and increase with the rise of compactness. The dynamic resilient modulus of silty clay is also affected by the stress condition, and it increases with the growth of confining pressure and decreases with the increase of cyclic deviator stress. A three-parameter composite model was used to predict dynamic resilient modulus of frozen and thawed silty clay, and a model for predicting shear wave velocity was also established. The conversion relationship between the dynamic resilient modulus and shear wave velocity was constructed, which could provide an effective way to determine the dynamic resilient modulus of subgrade soil based on shear wave velocity.

Key words: dynamic resilient modulus, shear wave velocity, silty clay, freeze-thaw cycles