3.8. (9/11) LANDSLIDES - hillslope transport Flashcards

1
Q

what are some characteristics of landslides?

A
  • internally crumbling and deforming
  • whole coherent mass moves
  • there is a slide plane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the slide plane?

A
  • a discreet plane below which there is no more movement
  • point of failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the difference between a creep and landslide?

A

mass moves above a plane at a constant rate whereas in creep the whole soil profile slowly moves downslope (velocity gradient too)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the conditions necessary for a material to move?

A

function of:
- slipperiness of the slide plane (wetness, pore pressure counteracts the weight of material, floats)
- stickiness
- weight
- the steepness of plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What would the texture of the deposit be as it moved down?

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the safety factor?

A

the forces resisting a landslide vs the forces driving it to become a landslide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the safety factor formula?

A

resisting force/driving force = C + σntanФ/τ = (C+ρghcos2α-μtanФ)/ ρghsinαcosα

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does a safety factor of less than one mean?

A

if the driving force is bigger than resisting = landslide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a safety factor of more than one?

A

if the resisting force is bigger than the driving force = stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does a safety factor of one mean?

A

instability, teetering edge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the different forces acting on a moving object?

A

friction, normal stress, and shear stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is W? what is its formula?

A

weight of the block
densitygravitational accelerationthickness*the angle that it’s at (cosα) on a slope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is σn? what is its formula?

A

normal stress: force that holds down object on plane
Wcosα

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is τ? What is its formula?

A

Shear stress: force pulling an object down a slope
Wsinα

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is C?

A

cohesion, y- intercept

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is f? what is its formula?

A

Friction: force holding object back against a slope
Wsinα/Wcosα = tanα

17
Q

What is μ? What is its formula?

A

the effective normal stress
ρghmcos2α

18
Q

What is m?

A

how saturated the object is (where 1 is the most saturated)

19
Q

In a shear stress-normal stress graph what is the slope called?

A

failure envelope or tanФ or how steep the line is

20
Q

What is tanФ?

A

angle of internal friction

21
Q

what is another way to write y = mx + b?

A

τ = tanФ*σn + C

22
Q

What is the equation for resisting force?

A

tanФ*σn + C

23
Q

What is the equation for the driving force?

A

τ (tau)