Bearing Capacity Characteristics and Failure Modes of Low Geosynthetic-Reinforced Embankments Overlying Voids

Abstract

Reinforcement solutions can ensure that low geosynthetic-reinforced (LGR) embankments progressively subside instead of suddenly failing due to void collapse, which provides an early warning to allow surface refilling to be carried out. This study investigates the characteristics of the bearing capacity and failure modes of the LGR embankments overlying voids using large-deformation finite-element analysis and normalization method. The system as a whole has six distinct failure modes: the trapdoor, sidewall, combination of roof and sidewall, rotational roof, combination of roof and single sidewall, and slope failure modes. Five types of slip lines exist for the LGR embankment: the vertical, trapezoid, double-cambered, partial-vaulted, and vaulted slip lines. This study also presents the effects of influencing parameters (e.g., rupture strength of the reinforcement, location and size of the void, and height and shear strength parameters of embankment fills) on the ultimate bearing capacity of the system. Design charts are obtained to determine the required soil properties and evaluate the characteristics of the bearing capacity of the system.