Numerical Investigation into the Arrangement of Clay Core on the Seismic Performance of Earth Dams

During earthquakes, the materials of earthfill dams undergo significant changes in their properties. These modified properties of the soil affect the stability of the dam. The most severe situation is dam failure due to liquefaction of the granular soils in the shoulders. The development of liquefaction is directly related to the excess porewater pressure that would develop during earthquake shaking. The generation and dissipation of excess porewater pressure is a phenomenon that depends on the drainage possibility and length of drainage path. Therefore, with some modifications on the slope of the dam, the clay core can assume different arrangements. These arrangements modify the seismic response of the dam. Numerical codes are useful tools to investigate the safety of dams in seismic prone areas. In this paper FLAC3D numerical tool is used. The influence of the arrangement of the clay cores of the dam on the development of porewater pressure and crest settlement of earthen dams, and hence seismic performance of earthen dams is investigated. Based on the numerical investigations, the performance of earthfill dams increases with increase in the angle of inclination of the center line of the core from the vertical towards the upstream. So the arrangements of the clay core for dams in seismic areas can be taken as one design criteria during earthfill dam design.