Ground Reaction of Lightly Overconsolidated Subsoil in Reinforced Piled Embankment under Cyclic Loads

Abstract

Subsoil support is generally ignored in the design of reinforced piled embankments, resulting in a very conservative design for settlement control. This design philosophy may lead to an unnecessary increase in construction costs, especially for embankments constructed over subsoil of medium and high compressibility (i.e., compression index of subsoil larger than 0.2). This paper presents the ground reaction of lightly overconsolidated subsoil in a reinforced piled embankment subjected to cyclic loads for the purpose of investigating the general behavior of lightly overconsolidated subsoil, and it promotes the sustainable development of piled embankment technology. The ground reaction of subsoil under both static and cyclic loads was comprehensively analyzed in terms of settlement and incremental vertical stress, which exhibited approximately the same profile. However, the settlement of lightly overconsolidated subsoil under a cyclic load was 23% larger than that under a static load. A parametric study was then performed under cyclic loads, and the results showed that the vertical stress carried by the subsoil was the most sensitive to the pile spacing amongst all the parameters considered in this paper. The analysis demonstrated an approximately 88% increase in stress when spacing was enlarged from 2.0 to 3.0 m. Finally, a modified analytical method for the ground reaction of lightly overconsolidated subsoil under cyclic loads was presented, and it showed reasonable agreement with the numerical simulation, particularly for relatively low geogrid stiffnesses, low embankment height (<6.5 m), and small pile spacing (e.g., 2–3 m center to center).