Computational Analysis of the Experimental Physical Model: Karstic Layer in Dam Foundation

Abstract

Karstic rocks (soluble rocks) exist in different areas of the world having useful/harmful structural and environmental impacts. One of the useful aspect is availability of rich water resources in some regions. An important defect of this kind of rocks is their low strength against water flows. These rocks usually dissolve in acidic water and as a result abundant caverns are created inside them. The gypsum and salt present in these rocks dissolve even in non-acidic water. Presence of these rocks in different foundations and reservoirs especially in dams could be potentially dangerous and cause enormous problems. If dams are located above soluble rocks like limestone, dolomite or gypsum they are endangered by karstification. Karstification is a dynamic process resulting in voids within the rocks due to dissolution. This dissolution leads to the formation of a pipe system within the sub-surface In the physical modeling, effects of cut-off wall height within gypsum layer were examined and monitored. Then with GeoStudio and Flac software, results of physical modeling are analyzed. In each experiment, cut-off wall height was changed. The result of the experiments indicated that as the gypsum Karst is very weak against water, cut-off wall must continue completely within the gypsum layer, as a complete positive cut-off wall.