Design of Barrage on Heterogeneous and Anisotropic Soils

The present study reports on the design of barrages on heterogeneous and anisotropic soils, based on the analysis of subsurface flow by finite element method. The study indicates that the location of impervious layer below the sheet piles marginally changes the uplift pressures, but with an advantage of reduction in the exit gradient. On the contrary, the location of a pervious layer below the sheet piles drastically changes the uplift pressures along with a drastic increase in the exit gradient and therefore, will have a major impact on the design of a barrage. The isotropic and anisotropic soils behave differently under subsurface flow considerations and unlike isotropic soils, the depth of upstream sheet pile/cut-off can be an important factor for the design of a barrage on anisotropic soils. The uplift pressures and exit gradients can be reduced by increasing the depth of upstream sheet pile for anisotropic soils.