2. SLOPE A small strip or patch of the land surfacethat is
inclined from the horizontal is mantled with regolith, which grades
downinto, unaltered rock called bedrock Regolith provides the
source f sediment,which consists of rocks and mineral particles
Soil and regolith blanket the bedrock, exceptin a few places where
bedrock is particularlyhard projects in the form of outcrops 3.
Slope Models1. Convex slope segments2. Concave slope segments3.
Rectilinear slope segments 4. Convex slope segments Form on the
upper parts of slopes Inresponse to soil creep and rain splash When
slopes are below the threshold for rapid mass wasting 5. Concave
slope segments Slopesegments that form near the base of slopes
Inthe absence of removal waste (e.g. river downcutting) With
increasing run off downslope, velocity and sediment transport can
be maintained over increasingly lower slope 6. Concave or convex?
7. Concave or convex? 8. Rectilinear Slope segments Straight
section of a profile Maydevelop on uniform rocktype where there is
only verythin covering debris 9. Factors controlling slopeform and
development 1. Climate 2. Geological structure 3. Nature of
regolith 4. Vegetation 10. Climate Different processes operate in
different climatezones and produce different slope forms and shapes
Humid areas slopes are frequently rounded due tochemical weathering
Arid region slopes are jagged or straight owing tomechanical
weathering and sheetwash Heavy rain and meltwater both add volume
and weightto the soil increases erosive power make slopeless stable
Heavy snowfall add weight conducive to rapidmovement (Avalanche)
11. Geological structureRocktype affect vulnerability to weathering
resistant to down slope movement 12. Nature of the regolith
Includes soil, scree, weathered bedrock and depositedmaterial.
Unconsolidated nature prone to downslope movement Increase weight
of deep regolith will increase thelikelihood of instability Clay
rich regoliths unstable because the ability to retainwater In a non
saturated soil- increases cohesion and reducesoil movement In
saturated soil the pore water pressure forces theparticle apart,
causing soil movement 13. Vegetation Can decreaseoverland run off
Lack of vegetationmeans there arefewer roots to bindthe soil
together 14. How do we get slope failure? Whenthe gravitational
force acting on a slope exceeds its resisting forces, slope failure
(mass wasting occur) 15. What is a shear strength? The resisting
forces that help tomaintain slope stability include the
slopematerials strength and cohesion The amount of internal
friction betweengrains and any external support of theslope known
as shear strength 16. How does the force gravityresulted in slope
failure? Gravity operates vertically but has a component acting
parallel to the slope causing instability The steeper the slope
angle the greater the component of force acting parallel to the
slope and greater the chances for mass wasting 17. Define angle of
repose The steepestangle that aslope canmaintainwithoutcollapsing
Angle ofrepose forunweatheredsolid rocksteeper than40 degrees 18.
What does it mean by when aslope is in a constant state ofdynamic
equilibrium?Means that they are constantly adjusting to new
conditions
