Natural Disasters Chapter 8: Slope Failures

Front 1

cohesion

Back 1

the attraction between small soil particles that is provided by the surface tension of water

Front 2

creep

Back 2

1) extremely slow downslope flow of sediment on the surface
2) slow, more or less continuous movement on a fault

Front 3

critical angle of repose

Back 3

maximum angle at which sediment particles can stand without falling

Front 4

debris flow

Back 4

a slurry of rocks, sand and water flowing down a valley. water generally makes up less than half the flow's volume.

Front 5

evapotranspiration

Back 5

water returned to the atmosphere by a combination of evaporation of water from the soil and leaves, and transpiration of moisture from the leaves

Front 6

fall

Back 6

a slope failure that involves vertically downward motion under gravity of a block without internal deformation or rotation

Front 7

flow

Back 7

in mass movement studies, a downslope movement of material along a surface involving internal deformaton

Front 8

fluidization

Back 8

the process of changing a soil saturated with water to a fluid mass that flows downslope

Front 9

frost wedging

Back 9

splitting of rocks through pressure exerted when water freezes

Front 10

gelifluction

Back 10

downslope creep driven by sequential freezing and thawing

Front 11

geotextile fabric

Back 11

strong permeable cloth that permits water to pass but not soil and rock particles

Front 12

grain flow

Back 12

style of mass movement involving particle contact, usually developed in gravel or sand

Front 13

landslide

Back 13

rapid downslope movement of material under gravity

Front 14

mudflow

Back 14

a flow of mud, rocks and water dominated by clay or mud-sized particles

Front 15

normal stress

Back 15

the component of stress perpendicular (normal) to one of Earth's planar surfaces

Front 16

perforated pipes

Back 16

pipes full of holes that are pushed into a water-saturated landslide. water seeps through the holes into the pipes and then down through the gently sloping pipes to the surface.

Front 17

permeability

Back 17

the ease with which water can move through soils or rocks.

Front 18

quick clay

Back 18

water saturated mud deposited in salty water tends to consist of randomly oriented flakes of clay with large open spaces between the flakes. if the salt is flushed out, the flakes are unstable and may easily collapse and flow almost like water.

Front 19

rock avalanche

Back 19

also known as "sturzstrom"

Front 20

rock bolts

Back 20

long bolts drilled into and expended in an unstable rock mass to help keep it from sliding

Front 21

rockfalls

Back 21

a rock mass that falls from a steep slope

Front 22

rotational slide

Back 22

the mass rotates as it slides on a basal slip surface (also called a slump)

Front 23

sackung

Back 23

a natural spreading fracture across a steep slope, caused by gravitationally driven downslope movement

Front 24

shear stress

Back 24

stress resulting from application of force parallel to a surface

Front 25

shotcrete

Back 25

a fluid cement-type material that is sprayed no a slope to prevent water penetration

Front 26

slope failure

Back 26

mass movements under the influence of gravity

Front 27

slump

Back 27

rotational landslide

Front 28

surface tension

Back 28

tension in a surface layer of water that causes it to behave as an elastic sheet

Front 29

topple

Back 29

slope failure that involves vertically downward motion under gravity of a block without internal deformation, but with rotation

Front 30

translational slide

Back 30

a landslide that moves approx. parallel to the slope of the ground