Evaluation of Solubility of Gypsum-bearing Piles and the Role of Water in its Leakage off the Pile in Fifty-year Return Period: Special Case of Marash Dam

Abstract

Gypsum and anhydrite in circumstances of fast water flux and high permeability is a manufacturing concern in the fifties. Experiences show that in low water flux zones, the solubility is less probable and it decreases if the environment is such that the water is saturated before getting in contact with gypsum-containing area. Hence evaluation of these materials towards the mentioned factors seems to be necessary. In current study the solubility of gypsum is measured in three solutions including distilled water, Marash Dam water, and distilled water plus 1% NaCl. Consequently, the values of solubility constant are measured and calculated using circulation analysis in the three solutions. Finally, the extent of fracture width during fifty years has been calculated and the amount of water leakage is assessed with high precision according to this value, regarding the water downfall (hydraulic gradient) in the dam’s body and gypsum-bearing zones. Results of circulation analysis (with constant hydraulic gradient) show that the progress of fracture’s radius decreases from the input towards the output. Additionally, along the water flow path, the growth of radius is more considerable in zones having purer gypsum in comparison with surrounding points.