Geosynthetic-reinforced soil structures with concave facing profile

This paper presents a new method to determine the optimal profile of facing elements in geosynthetic-reinforced soil structures. Flexibility of some facing systems and advances in construction technology allow construction of reinforced soil structures with a non-planar cross section. In this study, the facing profile of a concave geosynthetic-reinforced soil structure (referred to as CGRSS) is idealized by a circular arc defined by a single variable, the Mid-Chord Offset (MCO). For a given setback and elevation change, the optimal facing profile is determined by seeking the MCO which, for a given margin of safety, yields the least tensile load in the reinforcement layers. The proposed procedure for finding the optimal facing profile is incorporated into a limit equilibrium-based log spiral formulation to determine the required tensile strength of the reinforcement. Results are presented in a set of charts showing the required unfactored tensile strength, MCO, and mode of failure for various friction angles, batter angles, and seismic coefficients. It is shown that CGRSSs can decrease the required tensile strength of the reinforcement by up to 30% under static and pseudo-static conditions. This observation justifies employing concave facing profiles in practice.