3D Coupled Mechanical and Hydraulic Modeling of GESC-Supported Embankments under Cyclic Loads

Abstract

To date, the traffic-induced dynamic behavior of geosynthetic-encased stone column-supported embankments (GESC) under traffic cyclic loads accompanied by embankment consolidation has not been well studied. Three-dimensional (3D) coupled mechanical and hydraulic modeling is performed using FLAC3D, which considers the fluid flow during the lifespan of three stages: (1) embankment construction (EC): (2) consolidation (C) under embankment surcharge; and (3) cyclic loading (CYC). During the simulation, excess pore pressure, stress concentration, settlement, and lateral displacement are monitored, and the total settlement and lateral displacement could be easily obtained by accumulating the components of the three stages. Parametric analyses are conducted on the reinforcement forms and cyclic loading characteristics that include the dynamic stress amplitude and loading frequency. The ordinary stone (OSC) and GESCs could reduce the settlement and lateral displacement during each stage by improving the strength of the foundation and accelerating drainage consolidation; however, GESCs outperform the columns without geoencasement. In addition, the stress concentration ratio under embankment filling decreased with the increase in the dynamic stress amplitude and loading frequency, which led to the increase in the percentage of the cyclic loading-induced settlement to total settlement.