Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

2ND QUARTER > DRRR - Sinkholes & Landslides > Flashcards

DRRR - Sinkholes & Landslides Flashcards

1
Q

The downslope and outward mass movement of materials such as soils, debris, rock, and garbage

A

Landslide

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

Why do landslides occur? Enumerate

A

Removal of Support
Groundwater Pressure
Volcanic Eruptions
Earthquake
Human Interventions
Intense Rainfall

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

This is a cause that may be done due to erosion at the toe of a river or due to ocean waves

A

Removal Of Support

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

Sudden changes in level of bodies of water adjacent to the slope, also acts to destabilize it.

A

Groundwater Pressure

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

Used to determine if a slope is potentially prone to landslides

A

Mohr-Coulomb Criterion

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

Formula and components of the Mohr-Coulomb Criterion

A

τ - sheer stress
c - cohesion of the soil
σ - normal stress on the potential failure plane
ϕ - friction angle of the soil

τ | = c + σ tan ϕ

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

Building of slopes and the force of volcanic material or emission may also contribute to stopping instability.

A

Volcanic Eruptions

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

Slopes are prone to widespread failure during earthquakes because of the sudden shaking of hilly or mountainous areas

A

Earthquake

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

Human contributes to the instability of slopes through constructed activities

A

Human Interventions

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

Examples of human interventions

A
  • Excavation
  • Deforestation
  • Irrigation
  • Mining
  • Artificial Vibration
  • Water Leakage from Utilities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Landslides are triggered due to the weakening of the slope material by water saturation

  • 1 billion dollars are used to treat damages for this
  • 30 - 50 people die
A

Intense Rainfall

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

Top of the slope

A

Crown

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

Cracks at the top of the slope

A

Crown Cracks

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

First to fall down during landslide

A

Head

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

The zone that falls down during landslide

A

Zone of Depletion

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

The zone where materials are mostly stored or gathered by natural causes

A

Zone of Accumulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Concave downwards where depletion happens

A

Surface of Rupture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Body of landslide

A

Main body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

True or false?
Landslide occurs starting from what area weakens first

A

True. Landslides are caused by a case-to-case scenario depending on what weakens first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

“Landslides can be classified according to the type of slope materials and according to the type of movement”

A

David Varnes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Intact Mass

A

Rock

22
Q

20% - 80% of material are lesser than 2mm

A

Earth

23
Q

Commonly show slow movement along curved rupture surface

A

Rotational slides

24
Q

Rapid movements along a plane of distinct weakness between the overlying slide material and more stable underlying material.

A

Transitional slides

25
Q

Translational slide in which the moving mass consists of a single unit or few closely related units that move downslope as a coherent mass.

A

Block slides

26
Q

is the free or bounding fall of rock debris down steep slopes under the influence of gravity.

A

Rockfall

27
Q

failures involve the forward rotation and movement of a mass of rock, earth or debris out of slope.

A

Topple

28
Q

form of rapid mass movement in which a combination of loose soil, rock, organic matter, air, and water mobilize as a slurry that flows downslope

A

Debris Flow

29
Q

downslope viscous flow of fine grained material that has been saturated with water and moves under the pull of gravity.

A

Earth Flow

30
Q

Slowest type of mass movement. Imperceptible and continuous movement of material down a slope under the influence of gravity

A

Creep

31
Q

is the finite, lateral movement of gently to steeply sloping saturated soil deposits caused by earthquake-induced liquefaction

A

Lateral Spread

32
Q

How to reduce the effects of landslides?

A

The effects of landslides on people and structures can be lessened by total avoidance of landslide hazard areas or by restricting, prohibiting, or imposing conditions on hazard zone activity.

Individuals can reduce their exposure to hazards by educating themselves on the past hazard history of a site and by making inquiries to planning and engineering departments of local governments.

33
Q

Steps of landslide mitigation

A
  • covering the landslide with an impermeable membrane.
  • directing surface water away from the landslide.
  • draining ground water away from the landslide,
    minimizing surface irrigation.
  • Slope stability is also increased when a retaining structure and/or the weight of a soil/rock berm are placed at the toe of the landslide or when mass is removed from the top of the slope.
34
Q

a depression in the ground that has no natural external surface drainage. Basically, this means that when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface.

A

Silkhole

35
Q

Sinkholes form in what geologist call
- is a region where the bedrock can be dissolved by groundwater.

A

Karst Terrain

36
Q

Karst areas are characterized by special features not present elsewhere:

A

springs, caves, dry streams that lose water underground, and sinkholes.

37
Q

These different features all form because water that is slightly 1.) _____ from absorbing 2.) _____ _____ from the air and soil dissolves the bedrock that forms pathways and channels in the rock. If these pathways become exposed to 3.) _____ and if large enough can become 4.) _____

A

1.) Acidic
2.) Carbon Dioxide
3.) Erosion
4.) Caves

38
Q

How does a Sinkhole form?

A
  • Sinkholes form when water from rainfall moves down through the soil and encounters bedrock in karst terrain, the bedrock begins to dissolve along horizontal and vertical cracks and crevices in the rock and become large enough to start transporting small soil particles.
  • The surface of the soil above starts to slump down gradually and a small depression forms on the surface of the ground. This small depression acts like a funnel and gathers even more water, which makes the conduits larger and washes more soil into the conduit (Ex. Underground Water of Palawan)
  • If the soil contains a large amount of clay, the conduit can become plugged and sink-hole may start to hold water and form a natural pond.
39
Q

Occur in areas where limestone is exposed at the surface, or is covered by thin layers of soil or sand. Results in a gradual downward movement of the land surface and the development of a depression that collects increasing amounts of surface runoff.
- Erosion is caused by rains.
- The soil will go to the cavities and will make a pond.

A

Dissolution Sinkholes

40
Q

Occur where the cover material is relatively incohesive and permeable, and individual grains of sand move downward in sequence to replace grains that have already moved downward to replace dissolved limestone.

A

Cover-Subsidence Sinkholes

41
Q

Occur where a solution cavity develops in the limestone to such a size that the overlying cover material can no longer support its own weight. When a collapse occurs, it is generally very abrupt and can be catastrophic.

A

Cover-Collapse Sinkholes

42
Q

the space below the surface.

A

Spalling

43
Q

caused by erosion

A

Cavities

44
Q

New sinkholes have been correlated to land-use practices, especially from groundwater pumping and from construction and development practices. Some sinkholes form when the land surface is changed, such as when industrial runoff-storage ponds are created. The substantial weight of the new material can trigger an underground collapse of supporting material, thus causing a sinkhole.
Most caused is clogged pipes or leakage

A

Human-Induced Sinkholes

45
Q

Factors which increases of the chance of a sinkhole collapsing:

A

Adding weight
Buildings
Water Pumping
Construction
Environmental Factors
Raining
Drought

46
Q

What to do when a sinkhole appears?

A

1.) assess any changes to the drainage regime which may be causing the sinkhole to develop, and address these.
2.)

a. If the sinkhole is of no threat to people, livestock, property or infrastructure, then no immediate action needs to be taken besides fencing or ongoing monitoring of its development.

b. If the sinkhole does pose a threat, then take appropriate action, find an expert, such as a geotechnical engineer, who can advise on appropriate methods of remediation.

47
Q

Sinkhole Risk Mitigation

A

prohibiting or limiting development in the most hazardous areas through land use planning and regulations based on sinkhole susceptibility and hazard maps

Ensure that houses and roads are not constructed on or near caves

Never direct water towards sinkholes

Never dump rubbish in sinkholes

Reduce soil erosion

Promote plant cover - bare ground leads to poor soil structure enabling cavities to be exposed.

Controlling subsurface dissolution and subsidence processes involved in the generation of sinkholes

Preventing or controlling water withdrawal and the decline of the water table

Controlling irrigation to reduce the extra input of water into the ground.

Using efficient drainage systems and diverting surface drainage

Controlling subsurface dissolution and subsidence processes involved in the generation of sinkholes

Filling cavities in the rock or soil by grouting or sealing the covered rockhead by cap grouting Large cavities may be filled with rock fills through shafts or large diameter boreholes

Improving the ground by compaction grouting to increase the strength and bearing capacity of the soils

48
Q

involves the injection of appropriate materials under pressure into certain parts of the earth’s crust through specially constructed holes in order to fill, and therefore seal, voids, cracks, seams, fissures, or other cavities in soils or rock strata.

A

Grouting

49
Q

Typically performed by pumping a cement based grout with a slump of between 3 and 6 inches

A

Cap Grouting

50
Q

It is used to stabilize and densify compressible soils, and for liquefaction mitigation.

A

Compaction Grouting

51
Q

Done in order to collapse shallow cavities and detect soft material associated with karst features

A

Dynamic compaction

2ND QUARTER (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions