TRANSIENT PORE PRESSURES IN EARTH DAM

Abstract

The transient pore pressures in an earth dam, though at present not being used in slope stability computations, form a very important study. For a normal dam the reservoir lowering is time dependent and it would be quite appropriate to compute the draw down pore pressures at various reservoir drawdown levels and use them in the slope stability calcu- lations . In the present study the comparative study of mathema.-tical models given by Goel and Stephenson has been made. The study has shown that the Stephenson model is infact the same as that of Goel and has many inherent weaknesses such as use of Explicit solution scheme, use of simple triangular dam section and phreatic line corresponding to dam geometry. Improvement upon Goelos model has been made by incor-porating the condition that the nodes lying below the upstream slope should not have drawdown pore pressures at any time more than the reservoir level and also earlier pore pressures....