A Nonlinear Model for the Seismic Response of Geosynthetic-Reinforced Soil Structures

This paper proposes a mathematical model for the dynamic response of geogrid-reinforced soil under horizontal base excitation. First, a linear model of the soil without reinforcement is introduced, followed by a Newtonian nonlinear model for the dynamic response of soil with layers of geosynthetic reinforcement. The proposed model considers the following three effects of geogrid reinforcement on soil structures: (i) an increase of interlayer soil stiffness as a consequence of soil-geogrid interaction; (ii) an increase in the viscous damping as a consequence of the soil-geogrid interaction; and (iii) a further increase of the interlayer viscous damping, as a consequence of the geogrid-soil Coulomb friction. The proposed theory has been used to simulate the seismic response of two actual soil structures: a reduced-scale model of a soil retaining wall; and full-scale railway track retaining walls under a Kobe, Japan earthquake record. The results are encouraging and suggest directions for further refinement of the numerical model. Finally, a linearization of the Coulomb-type nonlinear model is proposed: an approximate viscous-equivalent model is presented, which provides a simple tool for performing a preliminary assessment of the order of magnitude of seismic effects.