Soil Creep - DOC

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					Soil Creep

What is mass-movement? Mass-movement is the down
slope movement of earth materials under the influence of
earth gravity. The detachment and the movement of earth
materials occur if the stress imposed is greater then the
strength of the material to hold its place.

What is it? (soil creep)

Soil creep involves a heave process whereby individual
particles rise and fall in response to expansion and
contraction due to wetting and drying or freezing and
thawing. It is the slowest process of all mass movement.
Soil creep is imperceptible to the naked eye and as I have
previously said, it is the slowest of all mass movement.

How does it work?

When water in the soil freezes the ice pushes the soil
particles outward perpendicular to the slope. However,
the ice melts and the soil is pulled down slope under influence of gravity. After many
freeze-thaw cycles the soils begins to move slowly down the slope. Possible methods of
seeing soil creep are by looking at trees, which have a curved trunk or root. Broke
retaining walls and curved railroad tracks also indicate creep in action.

Factors that influence soil creep?

Factors, which influence soil creep are mainly wetting and drying, and freeze thaw.
(Explanation is above)

Effects on landscape and human activity (roads, agriculture)

Soil creep will cause roads to be disrupted as the wetting and freezing underground will
create a

Real Life Examples:
“La Conchita, California has experienced devastating
landslides in recent years. Unstable slopes mobilized by rain
water caused a landslide and debris flow seen in Figure WM.5.
The city lies on a narrow strip of coast 250m (800ft) wide
between the shoreline and a 180 m (600ft) bluff above it.
Extraordinary rains and rising groundwater levels caused the
slope to fail, fortunately no one was killed. However, in
2005, another year of abnormally high rain fall caused the
slope to fail again, this time burying structures and killing
10 people.”

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