ERTH 2415 Lecture Notes - Lecture 10: Quick Clay, Silt, Tacticity
19 Jun 2015
School
Department
Course
Professor
Document Summary
Erth 2415 lecture 10 mass movements 1: mass movement downslope movement of earth materials under the direct influence of gravity. When driving force > resisting force then mass movement takes place. The driving force is the component of gravity parallel to the slope. Steepness and stability are indirectly proportional: removing support at the base of the slope, removal of lateral support decreases stability. Internal conditions of slope instability : presence of weak material, material that experiences plastic deformation due to stress e. g. clay. Friction force that resists motion between 2 surfaces in contact. Friction depends on the roughness of the surface and the presence of lubricants: fractures in rock fractures oriented in the slope direction are particularly unstable. Internal roles of water: adding weight to porous earth materials, dissolving cement binding minerals together. Salt binds the clay sheets and silt together: mass movements can occur in any type of rock, but sedimentary rocks are more likely to have mass movements.
