Characterization of permanent deformation of fine-grained subgrade soil under intermittent loading

Abstract

Understanding the permanent deformation characteristics of subgrade soils under traffic loads can provide a basis for subgrade design and evaluation. During repeated load triaxial (RLT) tests, accurate simulation of traffic loads is critical. RLT tests on silt under continuous loading and intermittent loading (cycles of continuous loading and intermittent stage) were performed using an RLT apparatus. The effects of the intermittent stage on the development of axial strain, pore water pressure and accumulated plastic strain were analyzed, and the dynamic behaviors of accumulated plastic strain under intermittent loading were also studied. The results show that the existence of the intermittent stage plays an active role in dissipating pore water pressure and improving the ability of the specimen to resist permanent deformation. Based on shakedown concept, an expression of critical stress and a prediction model for the accumulated plastic strain of silt under intermittent loading were proposed. The research results provide reference values for understanding the permanent deformation characteristics of silt.