(Similarity) Study on the Effectiveness of Earthfill Construction at the Lempake Dam Using Plaxis 2D Software

The construction of the embankment type dam is built through a process of stockpiling soil
material which is formed with a certain slope and height as well as the selection of a weir body zone that is
adapted to the soil conditions in the area. This can affect the stability of the dam body, especially during flood
and earthquake conditions. If these stability requirements cannot be met, it will have an impact on the safety of
the reservoir. To assess the stability of the Lempake Dam, Plaxis 2D software was used and then reviewed
under the following conditions: normal water level, flood and earthquake water level, and rapid drawdown
conditions. The data used as support in this study include topographic maps, hydrological analysis, analysis of
water availability, soil data and an overview of earthquake zones. After hydrological analysis, the flood
discharge for the 1000 year return period is 580.09 m3/second, the effective storage capacity is 0.43 x 106 m3.
The results of the stability analysis of the Lempake Dam using Plaxis 2D software Version 20 are quite safe.
When the normal water level is SF = 3,414, when the flood water level and earthquake is SF = 2,984 and
during the rapid drawdown SF = 2,819.
KEYWORDS: Dam, Lempake, Stability, Plaxis 2D