This section describes practical methods for representing pore water pressures in slope stability analysis, including TIN-based interpolation, phreatic surface approximations, and use of piezometric lines. The authors explain how pore-water pressures can be interpolated from finite element seepage analyses, how geometric assumptions influence accuracy, and how different representations (TIN, phreatic surface, piezometric line) affect computed factors of safety. Worked examples demonstrate that small differences in assumed water-pressure profiles can significantly change FS, especially in slopes with seepage or complex groundwater conditions.
