Energy Method for Analyzing the Large Deformation of Geogrid Cushions above Cylindrical Soil Cavities

Abstract

In regions prone to soil cavity development, geogrid-reinforced embankments must consider the impact of foundation settlement. This study models the geogrid cushion as a thin circular elastic plate, with the embankment's self-weight, vehicular traffic loads, and the frictional forces at the reinforcement-soil interface all translated into external loads. Utilizing the Pasternak model to simulate the foundation, we adhere to the principle of large deflection in thin plates to account for three types of strain energy and the work done by external loads, thereby deriving analytical expressions for the deformation of the geogrid cushion. We analysed the impact of embankment height, reinforcement-soil interface parameters, modulus of subgrade reaction, and the shear modulus of the foundation soil on the deflection of the reinforced-cushion. The findings reveal that when the embankment height surpasses the cavity diameter, its influence on differential settlement in anchorage areas becomes negligible. As the tangential resistance coefficient at the reinforcement-soil interface increases, its effect on differential settlement in the subsidence area progressively diminishes. The modulus of subgrade reaction influences differential settlement in anchorage areas but not in the collapsed area. The taller the embankment, the more significant the impact of the modulus of subgrade reaction in the collapsed area. When the embankment height and the thickness of the Pasternak shear layer are considerable, and the modulus of subgrade reaction is low, the effect of the foundation shear modulus on the deflection of the reinforced-cushion must be considered.