Static and Pseudo Static Analysis of Embankment Slope Stability of Bener Dam, Purworejo Regency, Central Java

The Bener Dam is considered as one of the largest rock-fill dams in Indonesia. This dam will impact the inundation area of three main villages in the Wonosobo and Purworejo regency. Since this zoned embankment dam consists of rock-fill and the core material, the stability of the dam slope has to be done to ensure that the dam is stable against any failures including the seismic effects. Moreover, the seismic coefficient in the study area in the seismic analysis of the large dam slope is needed to be used in the analysis which is not yet done from the previous studies. This paper presents the analysis of the embankment slope stability of the Bener dam under static condition and pseudo static condition. The analysis takes into account the end stage of construction, the steady-state stage, and rapid drawdown stage. The results of utilizing the Finite Element Method to analyse the slope stability demonstrates that the dam embankment slopes are stable under static and seismic stress conditions in all the reservoir condition stages. After applying the seismic loading, the result of safety factor of slope stability is reduced while the rapid drawdown stage has the lowest safety factor.