Static and Dynamic Responses of Geosynthetic-Reinforced and Pile-Supported Embankment of High-Speed Railway

Soil arching plays a major role in geosynthetic-reinforced and pile-supported (GRPS) embankment by load transfer mechanism. For the purpose of understanding the static and dynamic behavior of GRPS embankment, a two-dimensional plane strain simplified finite element model (FEM) of pile-supported embankment was established to examine the soil stress distribution in depth and pile efficacy on the surface of piled foundation. Due to the transmission of stress waves, the distribution pattern of dynamic stress was different with that of static stress. Besides, stress waves were reflected greatly when they arrived at the surface of piled foundation, which caused the greater additional stress than that of static train loading, and the dynamic pile efficacy was smaller than the static pile efficacy. Factors of speed of moving train, elastic modulus of subsoil, and embankment height were examined and showed that the elastic modulus of subsoil was the most sensitive factor to pile efficacy, especially dynamic pile arching. Finally, the distribution pattern of dynamic stress in depth was determined by the height of superstructure of piled foundation. Below the critical height of embankment, the dynamic stress distribution was dominated by the reflection of stress waves, but, when the embankment height exceeded the critical height, the soil stress above the height of soil arching could be calculated by Boussinesq solution.