Large-Scale Model Tests on a Bilaterally Wrapped Geogrid-Reinforced Embankment

The bilaterally wrapped geogrid-reinforced embankment is a new type of reinforced soil structures, and correct recognition on its performance is significant for practical design. Using a self-developed large-scale model test system, mechanical behaviors of the reinforced embankment under multistage strip surcharges are tested. The observed results reveal that the side panels of the embankment present a bulging pattern with larger horizontal displacements at the mid-height zone and smaller displacements at the upper and lower ends, and the maximum horizontal displacement is located at approximately 0.47 times the height of the panel. Compatibly, the mid-height layers of the geogrids also have more considerable tensile forces than those near the embankment top and bottom. Consequently, a concise cubic parabola mode of the tensile force of the geogrids along with the embankment height is put forward. In addition, the lateral earth pressure on the wrapped ends of the geogrids exhibits a nonlinear distribution mode with a smaller value at the top and a larger value at the bottom of the embankment. A comparison of the lateral earth pressure and tensile force of the reinforcements between the tests and existing empirical methods shows that the existing methods specified in some codes are too conservative for this novel earth structure.