Determining performance of two-tiered GRS walls subjected to traffic cyclic loading

This study evaluates the performance of two-tiered geogrid-reinforced soil (GRS) walls subjected to traffic cyclic loading considering several influence factors. These factors herein include the offset distance (D) of walls, the number (N), amplitude (Pmax), and frequency (f) of applied cyclic loading. Seven GRS walls with a reduced-scale of 1:3 were prepared in the laboratory and employed to investigate their (i) vertical foundation pressures during construction, (ii) load-induced settlements, (iii) facing lateral displacements, (iv) vertical and horizontal earth pressures, and (v) geogrid strains under the action of cyclic loading. Experimental results demonstrate that GRS walls constructed in tiered configurations can effectively reduce vertical foundation pressures. The increasing D, as well as the decreasing N and Pmax, introduces a reduction to the above five mechanical and deformation properties. However, increasing f results in the decrease of wall settlements and facing lateral displacements, and in the increase of others. Performance of several empirical equations for predicting the vertical foundation pressures, location of maximum geogrid strains, and failure surfaces inside walls was examined using the experimental data obtained in this study. Comparisons also were performed to describe the deformation and failure surface modes of the walls after loading.