Settlement assessment of sand subjected to cyclic stress related to a load moving over a surface using hollow cylindrical torsional shear apparatus

Abstract

Cyclic stress is applied to a soil element in the ground when vehicles or trains pass repeatedly on roads and railway tracks. This cyclic stress induced by traffic load gives rise to ground settlement, which sometimes causes damage such as cracks and ruts in road pavement. Therefore, estimating the settlement of granular materials is necessary for sustainable road design. For this study, a hollow cylindrical torsional shear apparatus was used to evaluate ground settlement induced by cyclic stress considering a moving load on the ground, which imitates a certain traffic loading condition.Results emphasize the importance of analyzing combined stresses including principal stress rotation because the vertical strain of the specimen depends strongly not only on the magnitude of loading but also on the type of loading. Although unstable deformation was not observed under drained conditions, the vertical strain increased linearly with the number of cycles of logarithmic scale. Relations among vertical strain, the magnitude of loading, and sand density were demonstrated based on experimentally obtained results.