Numerical Analysis of Soil Nail Walls in Hybrid Retaining Wall Systems

Hybrid retaining walls comprise 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 SN walls in such hybrid systems are limited. The purpose of this research is to numerically investigate the behavior of SN 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 SN wall with good agreement. The effect of nail length to total height (L-N/H-T), SNW facing slope (omega), nails inclination (alpha), and setback distance (d) on the tensile forces of nails in the SNW are studied. The results of tensile force distribution of nails are presented in this paper. The calculated tensile forces from the numerical modeling are compared with calculated values from SNW design methods using the Preliminary design charts, Simplified method, and Modified simplified method. Furthermore, the tensile forces of numerical modeling are equal or higher than the tensile forces of the simplified, modified simplified methods (empirical method), and preliminary design charts (limit equilibrium method).