Accumulated plastic strain behavior of granite residual soil under traffic loading

Abstract

In this study, the accumulated plastic strain (APS) of granite residual soil (GRS) under traffic loading is investigated via cyclic hollow-cylinder and triaxial tests. GRS is a special type of soil that is found widely in the hot and rainy areas of southern China. Because of insufficient understanding of the cumulative plastic deformation of GRS, how the dynamic stress amplitude, degree of saturation, effective consolidation stress, and stress path affect the APS under loading cycles is explored and analyzed. The results show that the effective consolidation stress inhibits the development of APS, whereas the dynamic stress amplitude promotes it. The APS of GRS increases with the degree of soil saturation, and its noticeable water-softening characteristics become the least favorable factor for soil deformation. The combined action of water softening and principal stress rotation helps to increase the APS significantly, and it leads to the emergence of an APS developmental curve that differs from the stable curve. Accounting for the water-softening characteristics of GRS and various stress conditions, a simple and easily adopted APS model is developed to predict the evolution of APS with loading cycles. Although specific to GRS in China, the findings of this study are expected to apply more widely to other weathered geomaterials.