10 - 2/11/10 MASS MOVE M E N T (MASS-WAST I NG) * * The...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
2/11/10 MASS MOVEMENT (MASS-WASTING) **The often spontaneous movement of Earth materials under the force of gravity. * move en masse (in bulk) * all occur on slopes; angle determines speed of movement * angle of repose : the balance of gravity and friction ; the driving and resisting forces * whether gravity over comes friction depends on: steepness of slope; weight, size, Mechanics: ** Driving force: gravity, delineated into two components 1) parallel to the sloping surface or shear stress ** increases as the slope increases; zero on a horizontal surface 2) perpendicular to the sloping surface or the normal stress ** decreases as the slope increases; zero on a vertical slope *Other stresses: tensile stress : tends to pull a rock or soil mass apart Compressive stress : reduce the void space of a rock, or pore space of soil strain: deformation in shape or volume by application of stress * a mass may respond to stresses in one of three ways: 1) as an elastic : returns to its original shape and size after t has been stressed 2) as a plastic : retains the size and shape imparted by stress (doesn’t bounce back)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
3) as a viscous : if it behaves as a fluid * most substances may exhibit combinations of two or all three of these
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 5

10 - 2/11/10 MASS MOVE M E N T (MASS-WAST I NG) * * The...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online