PENGARUH FLUKTUASI MUKA AIR RESERVOIR TERHADAP DEFORMASI DAN STABILITAS BENDUNGAN TANAH (UJI MODEL DI LABORATORIUM)

Beside its great benefits, an earth dam also contains potential hazard that may cause disaster to its surrounding environment when proper operation and maintenance is not taken. The failure of an earth dam usually begins with landslide symptom on the upstream and downstream slope. Such failure is also started with cracks in the embankment slope at the downstream, deformation in the dam body, and followed with collapsed of the embankment body. Such collapsed mechanism is significantly related to the fluctuation of water level and its interaction to the soil material of the dam body. This research analyzes the influence of the reservoir water level fluctuation to the earth dam deformation and stability.Experiment in the laboratory used a physical model of an earth dam built in a �drainage and seepage tank� and by controlling the velocity of rising and lowering water level. The composing material of the model body consisted of three types of soil variation: sand, mixture of 90% sand-10% silt, and mixture of 80% sand-20% silt. Three variation of upstream slope inclination were made: 1: