Numerical Analysis of Mechanically Stabilized Earth Walls in Hybrid Retaining Wall Systems

Hybrid retaining walls comprising a lower soil-nail wall (SNW) and a mechanically stabilized earth wall (MSEW) on top are typically needed in combined cut and fill wall sections such as in road widening. However, available literature and design guidelines on MSE walls in such hybrid systems are limited. The purpose of this research is to numerically-investigate the behavior of MSE walls in hybrid retaining wall systems during and after construction. Two-dimensional finite element models of different wall configurations are analyzed using PLAXIS 2D software. The base-line model is verified against a published case history of a monitored MSE wall with good agreement. The effect of the nail length to total height (L_N/H_T), SNW facing slope (ω), reinforcements vertical spacing (V_L), reinforcements stiffness (J), and MSEW facing slope (ψ) on the tensile forces in the MSEW are studied. The results of tensile force distribution of MSE wall are presented at this paper. The calculated tensile forces from the numerical modeling are compared with calculated values from MSEW design methods using the Simplified method, Structure stiffness method, and K-stiffness method. Furthermore, the tensile forces of numerical modeling are higher than the tensile forces of the K-stiffness method (empirical method) and equal or less than the tensile forces of Simplified Method and Structure stiffness method (Limit equilibrium method).