Abstract

• Upper Paunglaung dam is a 98 m high Roller Compacted Concrete (RCC) gravity dam on Paunglaung River. The main types of dam foundation rocks are meta-sandstone and granite. During the construction of dams, it is necessary to carry out the curtain grouting in order to ensure the seepage cut-off and reducing uplift pressure beneath the dam foundation. Single row curtain grouting with split-spacing method was used in Upper Paunglaung dam. Geological condition and geological model of dam foundation were made in order to get proper grouting design and grouting methods. Trail and final grout mix design was made based on the results of material used in grouting. Single grout mix with a water/cement (W/C) ratio of 0.8~0.75:1 (by weight) as a “stable grout mix” was used for all grouting stages. Based on the geological condition of dam foundation, upstage stage and downstage method were used in curtain grouting. Grout curtain efficiency is one of the most important factors to control seepage flow beneath the dam body to ensure its safety concerns. Hence, all grouting data were analysed in order to know the grout curtain efficiency of dam foundation and then correlation between Lugeon values and cement take. According the results, the correction between Lugeon values and cement take shows poor correction, however, the grout curtain efficiency was achieved 94% in average after grouting. In this paper, the application of curtain grouting in Upper Paunglaung dam and grout curtain efficiency are discussed.