Title 22 Slope Stability.pdf ✅

Geotech 10: Slope Stability 1. Modes of Slope Failure Fall  Detachment of soil and/or rock fragments that fall down a slope. Topple  Forward rotation of soil and/or rock mass about an axis below the center of gravity of mass being displaced. Slide  Downward movement of soil mass occurring on a surface of rupture. Spread  Form of slide by translation. It occurs by “sudden” movement of water-bearing seams of sands or silts overlain by clays or loaded by fills. Flow  Downward movement of soil mass similar to a viscous fluid. 2. Factor of Safety Generally, the factor of safety is defined as: FS = τ௙ τௗ Where: τ௙ = average shear strength of the soil τௗ = average shear stress developed along the potential failure surface The shear strength of a soil consists of two components, cohesion and friction, τ = c ᇱ + σ ᇱ tanφ ᇱ Where: c′ = cohesion φ′ = angle of friction σ′ = normal stress on the potential failure surface Factor of Safety with respect to Cohesion F௖ ᇱ = c ᇱ cௗ ᇱ Where: