LONG-TERM SLOPE STABILITY COMPUTATIONS FOR EARTH DAMS USING FINITE ELEMENT SEEPAGE ANALYSES

摘要

Current finite element software allows rigorous seepage analyses to be performed relatively easily. After such analyses are performed the results can be introduced in a slope stability analysis to define the pore water pressures. Although this requires that a substantial amount of interpolation be performed to compute pore water pressures along potential, trial slip surfaces from the values of pore water pressure at nodal points, the interpolation can be performed reliably and with only moderate amounts of computational effort. The triangle-based interpolation described in this paper and implemented in slope stability software provides a robust and efficient procedure for performing the interpolation. Unlike other procedures, which require that all of the points used for interpolation be examined to find the points used to compute the pore water pressures at any given point, the triangle-based scheme provides a very efficient scheme for locating the interpolation points. Typically less than 1.5 percent of the triangles in the triangulation had to be examined to find the triangle used for interpolation. Another advantage of the triangle-based scheme is that no extrapolation of values is required outside the perimeter of the points actually used for interpolation. Earlier schemes sometimes involved extrapolation of values that could lead to erroneous values of pore water pressure.