1. Slope stability I EOSC316 Engineering Geoscience

2. Landslip trigger processes Water Toe removal –Natural –Artificial Head loading Vibration

3. Folkestone Warren, Kent Toe erosion due to extension of harbour wall, 1905 Since 1915 slide –mass concrete toe weights –drainage adits

4. Mt. Huascaran, Peru, 1970 earthquake triggered hit towns of Yungay and Ranrahirca, 18 km away, at around 150 km/hr Yungay completely buried, 66,000 dead

6. Types of landslide Rock failure –failure plane pre- determined Soil failure –failure plane along line of max stress

7. Rock failure

8. Planar translational slip in rock  = angle of repose (= angle of friction) Factor of safety = shear force at failure / shear force

9. Wedge failure in rock

10. Toppling failure, Masada, Israel

11. Effect of cohesive strength on bench height in rock Shear stress on sliding plane: Failure occurs when: Thus Area of wedge

12. Half dome, YosemiteCarrara marble quarries, Italy

13. Rock failure – remedial measures

18. Slope failure in ‘unconsolidated’ material

19. Planar versus rotational slip in unconsolidated material Planar slip –frictional –cohesionless –C = 0 Rotational slip –frictional –cohesional –C ≠ 0

20. La Conchita, Santa Barbara, California, Spring 1995

21. Planar translational slip  = angle of repose (= angle of friction) Factor of safety = shear force at failure / shear force

22. Planar slip - analysis

23. Planar slip in soils Cohesionless soils (φ=0) Soils with cohesion (φ≠0)