The effect of soil suction in stability of partially submerged slopes

The paper deals with the stability of slopes under drawdown conditions taking into account the effect of negative pore-water pressures, usually neglected in routine analyses. A simplified unsaturated soil profile above the water table was assumed and soil suction was estmiated using a Brooks and Corey type soil-water characteristic curve. A parametric study was carried out to evaluate the influence of geometrical, physical and mechanical parameters of a simple slope. The results for complete and rapid drawdown conditions show that the factor of safety varies less than 10% for dams or reservoirs with initial drawdown ratios less than 0.3. Soil suction becomes more significant (safety factor variation up to 50%) for railway or road embankments with the water level at the base of the slope.