Engineering Rock Mechanics

Kinematic analysis OF slope instability mechanisms 3 1 9

and intersection

Lower angle limit 0"

Upper angle limit: friction or slope dip

Lower angle limit: (90-0) or 0"

Intersections

(a) Upper angle limit: 90"

and intersection

Normals Lower 4 angle limit 0"

Upper angle limit: friction or slope dip

Lower angle limit: (90-0) or 0"

Intersections

(b) Upper angle limit: 90"

Figure 18.6 Construction of instability overlay for direct toppling.