Lateral Thrust Distribution in Column-Supported Embankments: A Parametric Study via 3D Simulations

Lateral spreading design of column-supported embankments (CSE) requires estimating the driving lateral thrust as well as the portion of this thrust that should be resisted by geosynthetic reinforcement. A three-dimensional (3D) numerical parametric study was conducted for 128 scenarios using the finite difference method to investigate the lateral thrust distribution in CSEs. For each scenario, a 3D slice of the half-embankment geometry was analyzed, beginning with an undrained embankment loading and followed by the dissipation of excess pore water pressures. Incremental lateral earth pressures were calculated and integrated over depth at the embankment centerline and toe locations to obtain the driving and resisting thrusts produced by embankment loading, respectively. These were compared to the resisting geosynthetic tension at the centerline. Results show that: 1) the centerline driving thrust is largest in the undrained end-of-construction condition and is approximately two times larger compared to the long-term dissipated condition; 2) the foundation passive resistance at the toe is approximately 50% of the centerline thrust in the undrained condition; and 3) for geosynthetic stiffness in the range of 300 kN/m to 900 kN/m, the maximum resisting tension ranges from 2% to 7% of the driving centerline thrust in the undrained and dissipated conditions, respectively. Implications of these results for practice are discussed.