Conformal analysis of seepage below a hydraulic structure with an inclined cutoff

Abstract

SUMMARYConformal mapping techniques are used to obtain an exact solution for seepage flow below a hydraulic structure founded on permeable soil of infinite depth for a flat floor with an inclined cut-off at the downstream end. Results are presented for different values of b/s and 8. The exit gradient decreases considerably along a distance beyond the floor end with an increase in cut-off inclination. The maximum exit gradient decreases for B = 10,20 and 30 and starts increasing for B = 45 ' . The uplift pressure decreases as 8 increases. It is concluded that using an inclined cut-off increases the factor of safety in design against uplift and piping.

Permeability Coefficient of Concrete under Complex Stress States

“…Nevertheless, in the present safety analysis of hydraulic structures, concrete is usually viewed as an impermeable material [ 14 , 15 , 16 ], or as a material with a constant permeability coefficient [ 17 , 18 , 19 ], even though in the seepage–stress coupling analysis, the permeability coefficient varies mainly within the range of the material’s elastic state. Rivera [ 20 ] established the permeability coefficient as a function of porosity by groundwater experiments and applied it to geotechnical and concrete materials; Louis [ 21 ] established the relationship between the anisotropic permeability coefficient and stress using experimental data from borehole pumping experiments at a dam site.…”

Effect of Location and Angle of Cutoff Wall on Uplift Pressure in Diversion Dam

“…Solutions for various problems have been given by Harr (1962) applying conformal transformation. Ijam (1994) has analyzed seepage below hydraulic structures with an inclined cutoff at downstream end of the base of the structure. Construction of deep cutoff in front of the concrete structure of the dam to remedy the developed seepage problems has been discussed and presented by Di Cervia (2004).…”