Discrete element analysis of the development and evolution of “soil arching” within a piled embankment

“Soil arching”, as the major medium of load transfer for a piled embankment, has significant influences on the behaviors of load transfer and of embankment fill displacements. Based on the laboratory model tests, a series of numerical models by discrete element method (DEM) are established with the particle flow code PFC^2D to investigate the features and evolution of “soil arching” by analyzing the distribution of principal stress direction, contact force chains and embankment fill settlements. The numerical results indicate that the “soil arching” develops gradually with the increase of pile-soil relative displacement and maintains a relatively stable state finally. Meanwhile the relatively stable “soil arching” is roughly parabola-shaped with a height of 0.8 times the clear spacing of cap beam. Additionally, the embankment height has significant influences on the features and evolution of “soil arching”, as well as the load-transfer efficacy. However, the roughness of embankment fill, the clear spacing of cap beam and the width of cap beam have significant influences on the load-transfer efficacy, but not on the “soil arching” features.