Analysis of Large Embankment Dam in Case of Rapid Drawdown and Earthquake Aftershock

Dams and reservoirs are important as a source of freshwater as well as for regulating flooding and producing hydroelectricity. The same as with any other manmade structure, dams need to monitored and maintained to prevent disastrous failure. One of the events that can reduce the stability of an embankment dam is rapid drawdown. Rapid drawdown is when the water level decreases at such a rapid rate that the dam material(s) cannot drain and adjust to the change in time. Without the buttressing effect of the water, the upstream slope of the dam becomes less stable. Another threat to dam stability is earthquake shakings. Strong seismic event can cause damage to dams and appurtenant structures. The analysis is run in the program GeoStudio 2020 using existing data, reasonable estimation, well-accepted theories, and engineering judgment. The results of this study show that this mode of failure should be considered for embankment dams. The analyses results shows that Sirikit Dam outperforms the required factors of safety in the largest possible event of rapid drawdown and aftershock. This method of analysis can be extended to other embankment dams. Further research could estimate the probability of this event