Gypsum Dissolution Effects on the Performance of A Large Dam

Upper gotvand dam is constructed on the karun river located in the south west of iran.in this paper, 2d and 3d models of the dam together with the foundation and abutments wereconstructed and several seepage analyses were carried out. then the gypsum veins scatteredthroughout the foundation ground and also the seepage pattern were included in the models, hence thedissolution law of gypsum, was analyzed. it was disclosed that, the discharge fluxes obtained from 2dand 3d analyses are not similar and the discharge flux in 3d model is about 4 times the size of 2dmodel. also, the 3d model localizes the phreatic surface some what higher than the 2d model does.this means that the 2d model estimates lower pore water pressure pattern in comparison with the 3dmodel. these may be attributed to the fact that with 2d model the lateral components of vectors ofseepage velocity are ignored. in spite of the fact that the grout curtain is designed to be some 170meters deep, however, complete dissolving of gypsum will severely increase the discharge fluxthrough the foundation ground