Types-of-Slope-Movements and its importance.pptx

type of slope movement

1. Types of Slope Movements Slope instability can be classified into six different types of movement, each with distinct characteristics and behaviors. Understanding these classifications is essential for analyzing and predicting slope failures.

2. Classification of Slope Movements Falls Rapid movement through air with little ground interaction Topples Forward rotation about an axis below center of gravity Slides Movement along planar or curved failure surfaces Flows Viscous fluid-like movement without specific failure plane Creep Very slow movement over extended time periods Lateral Spreads Extension on gentle slopes with layered materials

3. Falls: Rapid Mass Movement Falls involve rapidly moving masses of rock or soil that travel mostly through the air with minimal interaction between the moving unit and ground. As material falls, it rolls and bounces with great force, shattering into smaller fragments. This type typically occurs on rock faces and provides little warning. Analysis is very complex and rarely performed. Key Characteristics Rapid movement through air Material shatters on impact Common on rock faces No warning signs

4. Gravitational Forces in Falls Gravity creates two force components that govern slope stability: Driving Forces (T) Forces pulling material downslope Resisting Forces (N) Normal forces creating friction resistance The interface develops resistance from friction: In terms of stresses:

5. Topples: Rotational Movement Toppling involves forward rotation of soil and/or rock mass about an axis positioned below the center of gravity of the mass being displaced. This mechanism is common in layered rock formations where vertical discontinuities allow blocks to rotate forward under gravitational forces.

6. Slides: Two Primary Types Translational (Planar) Movement occurs along planar failure surfaces running parallel to the slope. Controlled by discontinuities or weak bedded planes. Common when soils of significantly different strength are present. Rotational (Curved) Downward movement of soil mass occurring on an almost circular surface of rupture. Most common in cohesive soils and homogeneous materials. Note: Slides are the most common mode of slope failure and will be the main focus of analysis.

7. Flows, Creep & Lateral Spreads Flows Material moves like a viscous fluid without a specific failure plane shape. Can occur in high water content soils or dry soils. Common in quick clays, particularly in Norway. Creep Very slow movement of slope material occurring over long time periods. Identified by bent posts or trees indicating gradual displacement. Lateral Spreads Occur on very gentle slopes or flat terrain where a stronger upper layer undergoes extension and moves above an underlying softer, weaker layer.

8. Types of Slide Failure Surfaces Failure of slopes generally occurs along surfaces known as failure surfaces. Understanding these surface types is critical for stability analysis. Rotational Surfaces Circular surfaces occur in homogeneous cohesive soils. Non-circular surfaces develop in non-homogeneous soil conditions. Compound Slip Surfaces Form when a hard stratum at some depth intersects with the failure plane, creating a combined failure mechanism. Translational Slip Surfaces Develop when a hard stratum exists at relatively shallow depth, forcing planar failure along weak layers.

9. Course Focus: Stability Analysis This course will examine three primary types of failure surface analysis: Infinite Slopes Analysis of slopes extending indefinitely Finite Slopes with Plane Surfaces Planar failure surface analysis Finite Slopes with Circular Surfaces Rotational failure analysis Key Takeaway: Slides represent the most common mode of slope failure and will be our primary analytical focus throughout this course.