Abstract: Geosynthetics could be used for reinforcing embankment subjected to the influence of potential localised karst collapse. In this paper, the displacements and stresses in both embankment and geosynthetics, and the bearing mechanism of geosynthetic-reinforced embankment are analyzed in detail based on the numerical simulation results from PLAXIS^3D software by using large deformation analysis method with updated mesh function. Moreover, the influences of design parameters (including size of karst collapse, embankment height, geosynthetic’s tensile stiffness and properties of embankment soil) on the maximum settlements of embankment and the maximum tensions of geosynthetics are investigated. Results indicate that the maximum settlement of embankment is depended on whether a closed stress dome in embankment is formed, and the height of the stress dome is mainly related to the size of collapse and the cohesion of embankment soil. Geosynthetic’s tensile stiffness, embankment height, and internal friction angle of embankment fill have slight influence on the height of stress dome. The maximum longitudinal and transverse tensions of geosynthetics are related to the longitudinal and transverse stiffness of geosynthetics, and the differences of both maximum pavement settlement and strain in geosynthetics caused from uniaxial and biaxial geogrids are small.

Key words: localised karst collapse, geosynthetic-reinforced embankment, bearing mechanism, numerical analysis, soil arching effect