ERTH 2415 Lecture Notes - Lecture 4: Clay Minerals, Silt, Friction
28 Aug 2018
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Document Summary
Gravity: the driving force is the component of gravity parallel to the slope, the resisting force is proportional to inertia and friction, and counteracts the driving force. Conditions decreasing stability: adding mass high on a slope, steepening slopes, removing support at the base of the slope, fractures in rock, fractures oriented in the slope direction are particularly unstable. Friction: force that resists motion between two surfaces in contact, controlling factors, roughness of the surfaces, presence of lubricants. Si-o tetrahedron molecule: four oxygen ions surrounding a much smaller silicon ion, tetrahedra combine to form rings, chains, sheets and 3d structures. Clay: clay minerals, general term used to describe a variety of complex sheet silicates, structure is a stack of thin sheets, sheet surface is negatively charged. Attracts water molecules and positively charge ions: positive side of water molecules attracted by negative charges on the surface of clay sheets, water is a bipolar molecule with a positive and a negative side.
