Slope Stability Risk Assessment Of Embankment Dam, Case Of Ribb Dam

Abstract

The Probability Failure Or Reliability Of The Dam, Using Spencer, M-P And Janbu Method Of Slices. The Analysis Accounts The Spatial Variability Of The Input Variables And The Statistical Uncertainty Of The Input Parameters Of Unit Weight, Cohesion, Angle Of Internal Friction And Seismic Coefficient By Performing 115000 Monte Carlo Trials Within 0.5 Meter Soil Sampling Distance. The Pore Water Pressure Analysis Through The Dam Body Has Been Carried Out By Seep/W Finite Element Mesh Norm. The Factor Of Safety Was Used To Find The Critical Slip Surface Of Slope By Evaluating The Slip Surface That Got The Lowest Factor Of Safety. From The Selected Critical Surfaces, The Sensitivity Analysis, It Was Concluded That The Variation In Friction Angle Of The Shell And Foundation Materials Affect The Factor Of Safety More Than Any Other Material Parameter In Both Upstream And Downstream Slopes. For Rapid Drawdown, The Stability Is Much More Sensitive To Changes In The Rock Fill Material Friction Angle. The Materials In The Zoned Embankment Dam Were Assigned Some Variation For The Probability Analysis Which Showed That The Selected Slip Surfaces Had Probability Of Failure Which Is Much Greater Than The Acceptable Limit. The Reliability Of Index Value Is Also Unsatisfied Compared To The Acceptable Limit. The Most Critical Slip Surface Derived From Deterministic Analysis Is Not Necessarily Sufficient, But The Probabilistic Stability Analysis Is An Appropriate Estimation Of The Most Critical Slip Surface Search.