One of the negative effects of mine exploration is the emergence of acid mine drainage (AMD). Acid mine drainage can cause contaminations towards ground water and surface run-off that can affect the ecosystems, human, and structural buildings. Acid mine drainage management can be done with settling pond that works in a way to dam emerging acid drainage with a compacted soil embankment. Soil embankment that functions as pond body forms a slope that has failure and sliding potentials. Slope stability analysis is needed to know the slope’s safety level of sliding possibility. This final project research was being done in Azalea Pond’s construction project that will be functioning to process P T Kaltim Prima Coal’s acid mine drainage in Sangatta, East Kalimantan. The analysis was done in soil embankment that functions as the pond’s body, at existing condition with slope 1V:3H and recommendation with slope 1V:2H. The analytical calculation of soil embankment was done towards the soil bearing capacity. Stability calculation also done numerically with Slope/W program in two conditions: when the construction had been finished and water level variation in rapid drawdown condition. The data that being used as input in Slope/W program is a result of direct shear test, that being simulated a few times until a minimum safety number from many variations had been achieved. According to the embankment’s analysis result with 1V:3H dan 1V:2H slopes, the safest design is 1V:3H slope (existing condition). The analytical calculation result gave safety factor of 4,49 from soil bearing capacity analysis. These results are above the safety factor required (SF>3) and show that the subgrade is able to hold up the embankment’s weight. Numerical analysis result when the construction is fin ished is a safety factor of 3,08 in pond body’s upstream condition and 3,15 in pond body’s downstream condition. The minimum safety factor number in rapid drawdown condition (RL water level 12,45 m) is 1,34 in pond body’s upstream condition and 1,05 in pond body’s downstream condition. According to the analysis results, the recommended design for Azalea Pond Construction is 1V:3H slope with MDD (Maximum Dry Density) number of 1,76 T/m 2 , and OMC (Optimum Moisture Content) of 16,60 %.

One of the negative effects of mine exploration is the emergence of acid mine drainage (AMD). Acid mine drainage can cause contaminations towards ground water and surface run-off that can affect the ecosystems, human, and structural buildings. Acid mine drainage management can be done with settling pond that works in a way to dam emerging acid drainage with a compacted soil embankment. Soil embankment that functions as pond body forms a slope that has failure and sliding potentials. Slope stability analysis is needed to know the slope’s safety level of sliding possibility. This final project research was being done in Azalea Pond’s construction project that will be functioning to process P T Kaltim Prima Coal’s acid mine drainage in Sangatta, East Kalimantan. The analysis was done in soil embankment that functions as the pond’s body, at existing condition with slope 1V:3H and recommendation with slope 1V:2H. The analytical calculation of soil embankment was done towards the soil bearing capacity. Stability calculation also done numerically with Slope/W program in two conditions: when the construction had been finished and water level variation in rapid drawdown condition. The data that being used as input in Slope/W program is a result of direct shear test, that being simulated a few times until a minimum safety number from many variations had been achieved. According to the embankment’s analysis result with 1V:3H dan 1V:2H slopes, the safest design is 1V:3H slope (existing condition). The analytical calculation result gave safety factor of 4,49 from soil bearing capacity analysis. These results are above the safety factor required (SF>3) and show that the subgrade is able to hold up the embankment’s weight. Numerical analysis result when the construction is fin ished is a safety factor of 3,08 in pond body’s upstream condition and 3,15 in pond body’s downstream condition. The minimum safety factor number in rapid drawdown condition (RL water level 12,45 m) is 1,34 in pond body’s upstream condition and 1,05 in pond body’s downstream condition. According to the analysis results, the recommended design for Azalea Pond Construction is 1V:3H slope with MDD (Maximum Dry Density) number of 1,76 T/m 2 , and OMC (Optimum Moisture Content) of 16,60 %.

Kata Kunci : stabilitas lereng, simulasi numerik, kuat geser, pemadatan timbunan tanah, rapid drawdown