Seismic Fragility Assessment for Cohesionless Earth Slopes in South Korea

Seismic performances of earth slopes have been primarily assessed from the predictive models of a horizontal slope displacement as a function of characteristics of slope and ground shaking, based on Newmark or Newmark-type sliding block analyses. A seismic fragility curve of earth slopes has been barely investigated, but it could be useful for resilient analysis (e.g., repair cost, recovery time, and loss of life and property). This study aims to develop the seismic fragility curves of earth slopes in South Korea using finite element (PLAXIS 2D) simulations. We selected a single height of slope (10 m) and three slope angles of 20°, 30°, and 40° defining slope geometries that are representative of slope conditions in South Korea with cohesionless soil types. These conditions resulted in a total of 6 slope models. We considered 280 ground motions calculated by one-dimensional site response analyses for various site conditions. The fragility curves were constructed for three damage states (i.e., minor, moderate, and major) using the computed displacements from the simulations. It turned out that the fragility curves were highly dependent on slope angle and ground motion characteristics.