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Soils > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Who cares about dirt (soil)?

A
  1. Geologists
  2. Contractors
  3. Hydrologists
  4. Farmers
  5. Agronomists
  6. Soil chemists
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2
Q

Why does soil matter to a construction manager?

A

Most structures of all types rest either directly or indirectly upon soil. Proper analysis of the soil and design of the structure’s foundation are necessary to ensure a safe structure free of undue settling and/or collapse.

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3
Q

Soil is composed of particles, ___ and

___.

A

large, small

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4
Q

Soil includes :

A

solid matter, air, and water

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5
Q

Particles are the result of

A

of weathering (disintegration and
decomposition) of rocks and decay of
vegetation.

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6
Q

Cycles of rock disintegrating to form

A

soil, soil becoming consolidated under great pressure and heat to form rock, and so on.

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7
Q

Difference Between Soil and Rock:

A

If material can be removed without blasting, it is usually considered to be “soil,” whereas if blasting is required, it might be regarded as “rock.

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8
Q

Rock classification based on their origin and/or method of formation:

A
  1. Igneous 2. Sedimentary 3. Metamorphic
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9
Q

form when magma (molten matter) such as that produced by erupting volcanoes cools sufficiently to solidify

A

Igneous rocks

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10
Q

Being generally hard, dense, and durable, ______ often make good construction materials. Also, they typically have high bearing capacities and therefore make good foundation material.

A

igneous rock

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11
Q

can be coarse-grained or fine-grained, depending on whether cooling occurred slowly or rapidly.

A

Igneous rocks

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12
Q

Cool quickly and as a result these rocks are fine grained or has a lack of crystal growth.

A

Extrusive igneous rocks

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13
Q

Are formed from magma that cools slowly and as a result these rocks are course grained.

A

Intrusive igneous rocks

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14
Q

The most common coarse-grained igneous rock:

A

granite

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15
Q

A hard rock rich in quartz, widely used as a construction material and for monuments

A

granite

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16
Q

The most common fine-grained igneous rock. A hard, dark-colored rock rich in ferromagnesian minerals and often used in road construction.

A

basalt

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17
Q

what type of rock is granite?

A

Igneous

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18
Q

What type of rock is basalt?

A

Igneous

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19
Q

compose the great majority of rocks found on the earth’s surface.

A

Sedimentary rocks

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20
Q

They are formed when mineral particles, fragmented rock particles, and remains of certain organisms are transported by wind, water, and ice (with water being the predominant transporting agent) and deposited, typically in layers, to form sediments.

A

sedimentary rocks

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21
Q

Over a period of time as layers accumulate at a site, pressure on lower layers resulting from the weight of overlying strata hardens the deposits, forming _________.

A

sedimentary rocks

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22
Q

Can be identified easily when their layered appearance is observable.

A

Sedimentary rocks

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23
Q

The most common sedimentary rocks are

A

shale, sandstone, limestone, and dolomite.

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24
Q

The most abundant of the sedimentary rocks, is formed by consolidation of clays or silts.

A

Shale:

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25
Q
  1. Organic matter or lime may also be present.
  2. Have a laminated structure and often exhibit a tendency to split along laminations.
  3. They can become soft and revert to clayey or silty material if soaked in water for a period of time.
A

Shales

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26
Q

vary in strength from soft (may be scratched with a fingernail and easily excavated) to hard (requiring explosives to excavate).

A

Shales

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27
Q

Relatively hard shale makes a good _______.

A

foundation material

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28
Q

consisting primarily of quartz, is formed by pressure and the cementing action of silica (SiO2), calcite (calcium carbonate, CaCO3), iron oxide, or clay.

A

Sandstone:

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29
Q

Strength and durability of sandstones vary widely depending on

A

the kind of cementing material and degree of cementation as well as the amount of pressure involved.

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30
Q

generally good Construction materials.

A

Sandstones

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31
Q

is sedimentary rock composed primarily of calcium carbonate hardened underwater by cementing action (rather than pressure); it may contain some clays or organic materials within fissures or cavities.

A

Limestone

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32
Q

Its strength varies considerably from soft to hard (and therefore durable), with actual strength depending largely on the rock’s texture and degree of cementation.

A

Limestone

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33
Q

Limestone with what type of texture is low strength?

A

(A porous texture means lower strength.)

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34
Q

If strong, can be good foundation and construction materials

A

Limestone

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35
Q

are similar in grain structure and color to limestones and are, in fact, limestones in which the calcite (CaCO3) interbonded with magnesium. If strong, can be good foundation and construction materials

A

Dolomites

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36
Q

_______ are much less common at the earth’s surface than are sedimentary rocks

A

Metamorphic rocks

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37
Q

They are produced when sedimentary or igneous rocks literally change their texture and structure as well as mineral and chemical composition, as a result of heat, pressure, and shear.

A

Metamorphic rocks

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38
Q

can be hard and strong if unweathered.

A

Metamorphic rocks

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39
Q

sometimes contain weak layers between very hard layers

A

Metamorphic rocks

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40
Q

what type of rock is marble?

A

Metamorphic

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41
Q

What are soil particles the result of?

A

Soil particles are the result of weathering of rocks and organic decomposition.

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42
Q

Weathering is achieved by

A

mechanical (physical) and chemical means.

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43
Q

disintegrates rocks into small particles by temperature changes, frost action, rainfall, running water, wind, ice, abrasion, and other physical phenomena.

A

Mechanical weathering

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44
Q

causes of rock disintegration

A

breaking, grinding, crushing

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45
Q

causes chemical decomposition of rock, which can drastically change its physical and chemical characteristics.

A

Chemical weathering

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46
Q

This type of weathering results from reactions of rock minerals with oxygen, water, acids, salts, and so on. It may include such processes as oxidation, solution (strictly speaking, solution is a physical process), carbonation, leaching, and hydrolysis.

A

Chemical weathering

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47
Q

What are the three things chemical weathering can do?

A

Chemical weathering can

(1) increase the volume of material, thereby causing subsequent material breakdown;
(2) dissolve parts of rock matter, yielding voids that make remaining matter more susceptible to breaking; and
(3) react with the cementing material, thereby loosening particles.

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48
Q

The type of soil produced by rock weathering is largely dependent on _____.

A

rock type.

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49
Q

Soils can be categorized according to where they are ultimately deposited relative to the location of the _____.

A

parent rock

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50
Q

They remain where they were formed, simply overlying the rock from which they came.

A

Residual soils

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51
Q

They are formed when rock weathers at one site and the particles are moved to another location.

A

Transported soils

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52
Q

What are the four common transporting agents for particles?

A

(1) gravity, (2) running water, (3) glaciers, and (4) wind.

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53
Q

Geological Foundations of the Greater Cincinnati, including SW Ohio, N Kentucky, and SE Indiana are made up of what?

A

The Ordovician bedrock

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54
Q

It has layers of hard gray limestone alternating with soft gray shale. One thick rock unit, the Kope Formation, is mostly shale and therefore is particularly prone to failure.

A

The Ordovician bedrock, glacial deposits, and riverbank deposits.

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55
Q

They are more variable and their distribution is harder to predict.

A

The glacial deposits

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56
Q

Till, outwash sands and gravels, which are mined for construction aggregate in many stream valleys, and lake bed clays, the culprit in many damaging landslides. These are all classified as what?

A

Glacial deposits

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57
Q

They are lower in clay, consisting mostly of sandy silts. They make very attractive land for farming and for real estate development, but are prone to flooding.

A

The riverbank deposits

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58
Q

What are the three soil types?

A

Cohesive, Cohesionless, Organic

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59
Q

sticks together and acts in a plastic manner

A

Cohesive

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60
Q

like sand, will not hold a unified shape

A

Cohesionless

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61
Q

spongy, crumbly and highly compressible which is undesirable in construction

A

Organic

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62
Q

Three common types of cohesionlesssoils are ________.

A

gravel, sand, and silt

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63
Q 
• Large Bearing capacities 
• Small settlements (movements) 
• Good foundation materials for roadway
• Excellent retaining wall backfill material 
Easily compacted 
Well draining
•High shear strength for embankments 
• Loose sand is poor for construction
A

Construction properties of Granular soils

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64
Q

high permeability make them bad for earthen dikes or dams

A

Granular materials

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65
Q

The common type of cohesive soil is ____, which has particle sizes less than about 0.005 mm.

A

clay

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66
Q
  • Lower shear strength, properties change with water content
  • Plastic, expansive and compressible
  • Creep (deform) under long‐term loading
  • Prone to landslides (related to Shales; limestone, sandstone)
  • They expand when wetted and shrink when dried
  • Low permeability causing high lateral pressures (bad for retaining walls)
  • Impervious ‐excellent material for earthen dams and dikes
A

Cohesive soils construction properties

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67
Q
  • On the border between clayey and sandy soils.
  • Fine‐grained like clays but cohesionless like sands.
  • Undesirable engineering properties.
  • exhibit high capillarity and susceptibility to frost action, yet they have low permeabilities and low densities.
A

silty and organic soilds

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68
Q

What are three properties of silts?

A
  1. Undesirable for construction
  2. Susceptible to frost
  3. Low permeability
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69
Q

Five properties of organic soil

A
  1. Undesirable for construction
  2. Contains organic matter
  3. Highly compressible
  4. Strong odor
  5. Low shear strength
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70
Q

What are the two classifications of the soil types by particle size?

A
  1. The American Association of State Highway and Transportation Officials (AASHTO) system
  2. The Unified Soil Classification System (USCS)
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71
Q

Coarse‐grained(granular): Gravel and sand, with soil grains coarser than ____ , or a ____ sieve size.

A
  1. 0.075 mm

2. No. 200

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72
Q

_____ will a natural soil be encountered in which all particles are exactly the same size and shape.

A

Never

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73
Q

The Atterberg Limits, Hydrometers tests are for what kind of soils?

A

for fine Grained Soils

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74
Q

Sieve Analysis is for what type of soils?

A

for Coarse Grained Soils

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75
Q

If soil is varied what should you do to test the soils?

A

Modifications to tests may occur

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76
Q

In the case of most cohesionless soils, distribution of grain size can be determined by _____.

A

sieve analysis

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77
Q

Is similar to a cook’s flour sifter: It is an apparatus containing a wire mesh with openings the same size and shape.

A

A sieve

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78
Q

When soil is passed through a sieve, soil particles smaller than the opening size of the sieve will pass through, whereas those larger than the opening size will be ______.

A

retained

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79
Q

Certain sieve‐size openings between _______ mm are designated by U.S. Standard Sieve Numbers

A

4.75 and 0.075

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80
Q
  1. Diameterofsoilparticlesatwhich50%passes(i.e.,50%ofthesoilby weightisfinerthanthissize)
  2. Mediansizegivesan“average”particlesizeforagivensoilsample
A

(D50)

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81
Q

Thediameteratwhich10%passes

A

(D10)

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82
Q

CU is the what?

A

Uniformity coefficient, it describes the steepness of the curve.

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83
Q

What is the equation for CU?

A

CU = D60 / D10

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84
Q

Indicatestheirregularityofthecurve. WhereD60andD30arethesoilparticlediameterscorrespondingto60% and30%,respectively,passingonthecumulativegrain‐sizedistribution curve.

A

Cc=CurvatureCoefficient

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85
Q

What is the equation used to find the curvature coefficient?

A

Cc = (D30)2 / (D10 x D60)

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86
Q
  1. Indicates the irregularity of the curve
  2. where D60 and D30 are the soil particle diameters corresponding to 60% and 30%, respectively, passing on the cumulative grain‐size distribution curve.
A

Curvature coefficient

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87
Q

Particle sizes varying over a wide range and have

higher Cu values (15 or higher).

A

Well‐graded soils:

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88
Q

Poorly graded soils:

A
  1. A deficiency or an excess of some particle sizes (gap‐graded or skip‐graded)
  2. Most soil particles approximately the same size and have low Cu (uniformly graded soils)
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89
Q

What is Good—Cu, Cc, when it comes to Gravel well grade?

A

Gravel Well Grade

• Cu≥4 and1

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90
Q

What is Good—Cu, Cc, when it comes to sand well graded?

A
  1. Sand Well Graded

• Cu≥6 and1

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91
Q

Distribution of grain size is not determined by sieve

analysis because the particles are too small.

A

Cohesive soils:

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92
Q

Cohesive Soils Analysis Techniques:

A
  1. Hydrometer method:
    Process for indirectly observing the settling
    velocities of the particles in a soil–water mixture.
  2. Atterberg limits
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93
Q
  1. Calculates the drag force on a sphere as it travels through a fluid.
    F=viscous drag force acting on the sphere.
    r=radius of the sphere
    n= viscous drag of the sphere
    v = velocity of the sphere
    F = 6 pie r Nv
A

Strokes law

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94
Q

• Relates the terminal velocity of a freely falling sphere to the diameter of the sphere
• ________ is applied to soil particles in the _______.
• The individual particles will fall at different rates
• Taking readings over time w
ill indicate the particle sizes

A
  1. Stoke’sLaw

2. hydrometer test

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95
Q

determines particle sizes

A

Hydrometer

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96
Q

The big difference between silt and clay is its behavior in the _________.

A

presence of water

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97
Q

In 1911 Atterberg defined the states of soils based on the ________.

A

Moisture Content

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98
Q

Plastic and Liquid Limit tests combined to form _________, which classifies the firmness of silts and clays. Evaluate soil for shrink/swell with changes in moisture

A

Atterberg Limits Test ASTM C4318

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99
Q

Consistency refers to clays or silts degree

of _______.

A

firmness

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100
Q

What are the four states of soil in Atterberg limits?

A
  1. Liquid state
  2. Plastic state
  3. Semi-solid state
  4. solid state
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101
Q
  1. The dividing line between the semi‐solid and solid states
  2. Quantified for a given soil as a specific water content, and from a physical standpoint it is the water content that is just sufficient to fill the voids.
A

Shrinkage limit

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102
Q

Below the ________, any water content change
will not result in volume change; above the shrinkage limit, any water content change will result in an accompanying volume change.

A

shrinkage limit

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103
Q

Soil moisture content when a reduction of water causes the soil to act as a solid. From semi‐solid to plastic state.

A

Plastic Limit

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104
Q

What are the sets to the plastic limit test?

A
  1. Water is added to soil in small amounts.
  2. Soil is molded into balls and then rolled into a thread or snake.
  3. If the snake crumbles before it reaches 1/8” diameter, it is too dry and more water is added.
  4. When the snakes is rolled and reaches 1/8” diameter,
    moisture is removed by remolding or evaporation.
  5. Continue the process until the snake crumbles at 1/8”.
  6. Determine weight with moisture.
  7. Repeat process with additional samples.
  8. Dry all samples and compare dry weight to
    wet weight.
  9. Not all soils have a plastic limit
  10. A material with no plastic state is called non‐plastic “NP” (silts or organics)
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105
Q
  1. Soil moisture content when an increase in water causes the soil to act as a liquid.
  2. From liquid state to plastic state
  3. Casagrande device & grooving tool
A

Liquid limit

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106
Q
  1. Three samples are used.
  2. Water is added to the sample.
  3. The sample is placed in the Casagrandedevice and smoothed until flat and 1/3” deep.
  4. Groove placed in the sample
  5. Casagrandedevice is tapped in order to close the gap
  6. Moisture content is determined by oven drying the sample
A

liquid limit test

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107
Q

What is the equation for plastic index?

A

PI = LL - PL

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108
Q

The ___ gives an indication of how much a soil will expand and contract. The higher the ___ the more exp./cont.

A

PI

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109
Q

Typical PI’s range from ____.

A

2-30

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110
Q
  1. In the field, _______ are a guide for how much settlement or consolidation will occur under load.
  2. Find the field moisture content and compare it to the _________.
  3. Field Moisture is near the Liquid Limit,&raquo_space; settlement is likely
A

Atterberg limits

111
Q

Why is it important to use atterberg’s limit to figure out how much soil will expand?

A
  1. All loads transfer to the soil

2. If foundations move…there is a problem!

112
Q

Three reasons for movement:

A

1.Settlement –downward movement of foundations due to consolidation of underlying materials.
2. Shrink / Swell –vertical movement, either downward or upward, caused by moisture changes.
3.Shear Failure –downward movement of the foundation by lateral
movement of underlying soils

113
Q

What are the three types of settlement?

A
  1. Uniform settlement
  2. Tipping settlement (mostly without cracks)
  3. Differential settlement (with Cracks)
114
Q
  1. Geological Classification System
  2. Agronomic Classification System
  3. Textural Classification System (USDA)
  4. American Association of State Highway Transportation Officials System (AASHTO)
  5. Unified Soil Classification System (USCS)
  6. Federal Aviation Agency System (FAA)
A

Various soil classification systems

115
Q

Soil classification systems must be:

A
  1. Based on a Scientific Method
  2. Simple
  3. Permit Classification by Visual and Manual Tests
  4. Describe Certain Engineering Properties
  5. Should be Accepted to All Engineers
116
Q
  1. Used by the US Department of Agriculture
  2. Limits are assigned for the soil fractions
  3. Mostly sand, some clay–So, sandy clay
  4. Deal with superficial soils
A

Textural classification

117
Q
  1. Silty clay
  2. Clayey sand
  3. Sandy gravel
  4. Need size limits on soil fractions
  5. Establish percent compositions
  6. US Department of Agriculture
  7. Particularly where characteristics of only superficial soils are of principal concern, which for construction purposes they frequently are.
A

Textural classification USDA

118
Q

When using Textural classification USDA, Gravel is not in chart. If soil contains ____ or more gravel, a gravelly prefix is added to classification.

A

20%

119
Q

Grain Size Distribution

A
  1. Mechanical Sieve Analysis

2. Well, Poor, or Gap

120
Q

When dealing with coarse grained soils, what affects the Shape of Particles/ Angularity?

A
  1. Manufactured Aggregate‐Angular
  2. Crushed Stone or Interlocking
  3. Natural Deposits
  4. Rounded or River Rock
121
Q

When dealing with _______is the ( % passing #200).

silt of clay

A

Fines Content

122
Q
  1. Do not retain the in‐situ properties
    of the soil during the collection process.
  2. Consider these samples to be representative of underground soils except for tests that do not rely on the structure of the soil itself.
  3. For soil type and texture, moisture content, and nutrient and contaminant analysis, among other evaluations.
  4. The majority of soil samples engineers and geologists collect are disturbed samples because they are easier to collect and the precision necessary for collecting an undisturbed sample is not required for many soil tests.
A

Disturbed soil samples

123
Q
  1. soil samples retain the structural integrity
    of the in‐situ soil.
  2. Collecting a perfectly undisturbed sample is difficult and the samplers may contain a small portion of
    undisturbed soil at the top and bottom of the sample length.
  3. Undisturbed samples allow an engineer to determine the geotechnical properties of strength, permeability, compressibility and fracture patterns among others.
  4. Results of these analyses are instrumental in the design of a new building.
A

Undisturbed soil samples

124
Q
  1. Shelby Tube (Thin Walled)/SPT (Standard Penetration Test):
  2. Retrieve a sample with an auger and tube leaves soil as intact as can be (almost in situ…):
  3. Truck mounted, like drilling rig
A

Undisturbed (kind of)

125
Q
  1. Taken by shovel, post hole digger, handheld auger
  2. Sealed to retain moisture
  3. All granular soils are taken this way
A

Disturbed soil sample

126
Q

Types of soil samples:

A
  1. Disturbed

2. Undisturbed kind of

127
Q

When doing Visual Soil Classification identify soil by using what three easy methods?

A
  1. Color (e.g. brown, gray, brownish gray)
  2. Odor (if any)
  3. Texture (coarse or fine‐grained)
128
Q

When doing Visual Soil Classification Identify the major soil constituent ________.

A

(>50% by weight)

129
Q

When using Visual Soil Classification Identify the major soil constituent (>50% by weight) for what types of soils?

A
  1. Coarse gravel
  2. Fine gravel
  3. Coarse sand
  4. Medium sand
  5. Fine sand
  6. Fines (clay and silt)
130
Q

Visual Soil Classification:

Estimate percentages of all other soil constituents by weight:

A
  1. Trace ‐0 to 10%
  2. Little ‐10 to 20%
  3. Some ‐20 to 30%
  4. More ‐30 to 50%
131
Q

Little

A

10 to 20%

132
Q

Trace

A

0 to 10%

133
Q

When doing a visual soil classification test, if major soil constituent is Sand or Gravel:

A

Identify particle distribution. Describe as well graded or poorly graded

134
Q

soil consists of particle sizes over a wide range.

A

Well‐graded

135
Q

Consists of particles which are all about the same size or gap graded

A

Poorly graded soil

136
Q

Visual Soil Classification: Identify particle shape (granular soils)

A
  1. Angular
  2. Sub‐angular
  3. Rounded
  4. Sub rounded
137
Q

Visual Soil Classification: If major soil constituents are

Fine particles, perform the following tests:

A
  1. Dry strength test
  2. Dilatancy Test
  3. Plasticity or Toughness (Snake) Test
138
Q

Field / Visual Classification:

  1. Rely on eyes to determine coarse vs. fine
  2. Well graded vs. poorly graded
  3. If soil is coarse but has fines:
A

Must run field tests to determine the classification of the fines.

139
Q
  1. Passing #40 material, moist soil
  2. Shake, squeeze
  3. The rapidity appearance of water during shaking, and disappearance when squeezing
  4. Is the soils reaction to shaking.
A

Dilatancy

140
Q

1.Fine clean sands reaction to dilatancy:

A

quick reaction

141
Q
  1. Plastic clay reaction to dilatancy:
A

no reaction

142
Q
  1. Inorganic silts reaction to dilatancy:
A

Moderate reaction

143
Q

Visual classification of fine grained soils:

  1. crushing characteristics of soil
  2. Passing #40 material, dry it
  3. Test its strength by breaking with fingers
  4. Fat clays –high strength
  5. Silt –slight strength
A

Dry strength

144
Q

Visual Classification of Fine Grained Soils:

  1. ________ –consistency near plastic limit
  2. Passing #40 material, moist
  3. Roll out like the Plasticity Index test
  4. Lean Clays –weak thread near plastic limit
A

Toughness

145
Q

Why Do We Classify Soils?

A
  1. Engineering applications based on the soil characteristics
  2. Safety Regulations on Trenching
  3. Max allowable slope for a Clayey Soil vs. Sandy Soil
  4. Suitable Fill
  5. Low Volume Change (LVC)
146
Q

Soil is made up of solids, liquids and gas.

A

Soil Components

147
Q

Are the soil that are visible.

A

Solids

148
Q

Are typically water, although petroleum and other _____ may be present.

A

Liquids

149
Q

Gas is also called _____ and has many constituents.

A

air

150
Q

The volume of the liquid and gas is known as the ____.

A

void

151
Q

Soil components

A

Air, Water, Solids

152
Q

Relative Density:

  1. For cohesionless soils
  2. Relative density can be defined in terms of ______.
A

Void Ratio; e

153
Q

Highest void ratio possible for a given soil (void ratio of the soil in it’s loosest condition)

A

e max

154
Q

Void ratio of the soil in place

A

e0

155
Q

lowest void ratio possible for the soil (void ratio of the soil in its densest condition.

A

e min

156
Q
  1. Developed by Arthur Casagrade
  2. To classify soils for use in roads or airfields
  3. Permits Field or Lab Classification
  4. ASTM D2487
A

Unified Soil Classification System

157
Q

Unified soil classification system classifies soils into six major soil types based on?

A
  1. Particle size
  2. Liquid limit
  3. Plasticity index
158
Q

Unified soils classification system uses a _______.

A

Two-symbol designation

159
Q

The first symbol in Unified soils classification system classifies what?

A

soil type

160
Q

G

A

gravel

161
Q

S

A

sand

162
Q

M

A

silt

163
Q

C

A

clay

164
Q

O

A

organic

165
Q

Pt

A

Peat

166
Q

is an accumulation of partially decayed vegetation or organic matter.

A

Peat

167
Q

What does the second symbol in the Unified Soils Classification system designate?

A

Condition of soil with respect to Gradation or plasticity

168
Q

W

A

Well Graded

169
Q

P

A

Poorly Graded

170
Q

L

A

Low liquid limit: LL less than 50

171
Q

H

A

High liquid limit: LL greater than 50

172
Q

NP

A

Non-plastic

173
Q

M

A

silty

174
Q

C

A

clayey

175
Q

If less than 5% passes the No. 200 Sieve Gravels and Sands are classified as?

A

GW, GP, SW, or SP

176
Q

When dealing with Gravels and Sands, the well verses poorly graded depends upon the ______.

A

particle size distribution

177
Q

When dealing with Gravels and sands, if more than 12% passes the No. 200 Sieve

A

GM, GC, SM, or SC

178
Q

When dealing with gravels and sands, iff between 5% and 12% of the material passes the No. 200 Sieve

A

GW‐GC Well‐graded gravel with clay

179
Q

SW‐SC

A

Well‐graded sand with clay

180
Q

GP‐GC

A

Poorly‐graded gravel with clay

181
Q

SP‐SC

A

Poorly‐graded sand with clay

182
Q

When dealing with gravels and sands, if between 5% and 12% of the material passes the No. 200 Sieve.

A
  1. GW‐GM Well‐graded gravel with silt
  2. SW‐SM Well‐graded gravel with silt
  3. GP‐GM Poorly‐graded gravel with silt
  4. SP‐SM Poorly‐graded sand with silt
183
Q

Fine grained soils:

A

ML, OL, CL, MH, OH, CH

184
Q
  1. If more than 50% passes the No. 200 sieve

2. If the Liquid Limits are less than 50

A

ML, OL, or CL

185
Q
  1. If more than 50% passes the No. 200 sieve

2. If the Liquid Limits are greater than 50

A

MH, OH, CH

186
Q

This determines whether sample is Coarse or Fine Grained.

A

% Passing the No. 200 Sieve

187
Q

This separates gravel from sand

A

% Passing No. 4 Sieve

188
Q

(Difference between liquid limit and plastic limit; ___ )

A

LL‐PL

189
Q

Coarse

A

(More than 50% on #200)

190
Q

less than 5% fines, greater than 12% fines (#200)

A

clean or dirty

191
Q
  1. Determine Cu, Cc

2. Determine Well or Poor

A

Clean

192
Q

Determine LL, PI –Plot on Plasticity Chart

Determine Silty or Clayey

A

Dirty

193
Q

To determine is a soil is fine grained, ___ or more passes #200.

A

50%

194
Q

Determine if organic:

A

must be told it is organic or has odor

195
Q

Plot on Plasticity chart to determine if ____.

A

Silt or Clay

196
Q

If soils have less than 5% fines_________.

A

Atterberg’s limits are irrelevant

197
Q

_____ should be determined by their dark color and smell.

A

Organic soils

198
Q
  1. Can determine by running LL on sample after air drying and oven drying.
  2. If LL is <3/4 the standard value due to drying it is ____.
A

organic

199
Q
  1. Describe soils with seven basic soil groups
  2. A-1(best) through A-7(worst)
  3. A-8 is for organic soils
  4. A-1 through A-3 are sands and gravels
  5. A-4 through A-7 are silts and clays
A

AASHTO classification system

200
Q

Best soil in AASHTO

A

A-1

201
Q

Worst soil in AASHTO system

A

A-7

202
Q

Organic soils in AASHTO system

A

A-8

203
Q

Sands and soils in AASHTO are classified as what?

A

A-1 through A-3 are sands and gravels

204
Q

Silts and clays are classified as what in AASHTO?

A

A-4 through A-7 are silts and clays

205
Q

What is the difference between ASSHTO and USCS?

A

Fine and course soils:
AASHTO defines fines as greater than 35% passing
USCS defines it as 50% passing .

206
Q

GI = (F - 35) (0.2 + 0.005(LL-40)) + 0.01(F-15) (PI - 10)

A

GI = group index

207
Q

For A-2-7 and A-2-6 use what?

A

Partial Group index

208
Q

PGI = 0.01 (F-15) (PI - 10)

A

Partial Group Index

209
Q

F = fines _______.

A

(#200 or 0.075 mm passing)

210
Q

If you have a negative GI what should you do?

A

report it as zero

211
Q

Refers to a volume of earthen material that is placed and compacted for the purpose of raising the grade of a roadway (or railway) above the level of the existing surrounding ground surface.

A

Embankment

212
Q
  1. Grain size distribution
  2. Particle shape
  3. Specific gravity of solids
  4. Clay
  5. Maximum dry unit weight (density)
  6. Optimum moisture content
A

The factors that affect Compaction of soils.

213
Q
  1. Typically 8” loose compacted to 6” at finish
  2. Typically accomplished in 6-10 coverages
  3. Scarifying between layers: to provide bonding between layers
A

Field Compaction

214
Q
  1. Tampers deliver a succession of light blows
  2. Held in place
  3. Operated by hand
  4. Used in areas not accessible by larger equipment
A

Ramming or tamping foot compactors (Wacker Packer)

215
Q
  1. Uses 1 or more rollers
  2. Self-propelled or pulled by tractors
  3. Compacting base courses, and provides a smooth finished grade
A

Smooth Drum

216
Q
  1. Vibration frequencies of 1,500-2,000 cycles/min

2. Effective for clean sands & gravels

A

Vibratory rollers

217
Q
  1. rotating drum with metal “feet”
  2. Creates greater pressures
  3. Provides kneading action for fines-grained soils (clays & silts)
A

Sheepsfoot roller

218
Q

–are the index values for fine particles

  1. Not always enough information to draw conclusions about soils.
  2. Need info on
  3. Soil Unit Weight
  4. Water Content
  5. Other correlations between air-water-soil
A

LL, PL, and PI

219
Q
  1. This number indicates how much heavier/lighter a material is than
    water.
  2. In soils, SG refers to the mass of solid matter of a given soil sample as
    compared to an equal volume of water.
A

Specific Gravity

220
Q

When dealing with specific gravities soil solids = what?

A

W= 187.2 lbs

221
Q

When dealing with specific gravities of water, it equals what?

A

W = 62.4 lbs

222
Q

If the W of the soil solids w=187.2 lbs and the w of the water w=62.4 lbs what is the specific gravity.

A

SG = 187.2 / 62.4 = 3.0

223
Q

Specific gravity of Sand is:

A

2.65-2.67

224
Q

Specific gravity of silty sands is:

A

2.67-2.70

225
Q

Specific gravity of Inorganic Clay is:

A

2.70-2.80

226
Q

Specific gravity of soils with mica/iron:

A

2.75 - 3.00

227
Q

Specific gravity of organic soils:

A

less than 2.00

228
Q

Soil Consists of the following:

A
  1. Solids
  2. Water
  3. Air
229
Q

What is the equation for the volume of soil.

A

Volume = volume of soil + volume of water + volume of air

230
Q

What is the equation for weight of soil?

A

water = water weight + water weight

231
Q

Vt=

A

Total soil volume

232
Q

Va =

A

Air volume

233
Q

Vw =

A

Water volume

234
Q

Vs =

A

solids volume

235
Q

Vv

A

voids volume

236
Q

What is the equation for void volume?

A

Vv = Va + Vw

237
Q

Wt =

A

total weight

238
Q

WW=

A

Water Weight

239
Q

WS=

A

Solids Weight

240
Q

What is the equation for void ratio?

A

e = Vv / Vs

241
Q

What is the Porosity (N) ratio?

A

n = Vv/V x 100%

242
Q

What is the degree of saturation (S) Stopped on page 8 of 2.6. A little confused.

A

S = Vw/Vv x 100%

243
Q 
1. Natural decrease in soil volume w
hen subjected to an increased 
effective stress
2. Foundations (surface loads)
3. Embankments (fill)
A

Compressibility

244
Q
  1. Results in surface settlement

2. Which in turn can cause damage to structures

A

compressibility

245
Q

Total settlement as a two‐phase process:

A
  1. Immediate settlement : occurs very rapidly—within days or even hours after a structure is loaded.
  2. Consolidation settlement: occurs over an extended period of time (months or years) and is characteristic of cohesive soils.
246
Q
  1. ________ involves expelling water from soil voids.

2. Due to permeability and void ratio (e)

A

consolidation

247
Q

High permeability = ______ soils (sandy)

2. Consolidation happens quickly; i.e. during construction

A

coarse grained

248
Q
  1. Low permeability = ________
  2. Consolidation happens slowly: Because of lower permeabilities, cohesive soils compress much more slowly because the expulsion of water from the small soil pores is so slow.
A

fine grained soils (clays)

249
Q
  1. Change in height can be predicted based on the loaded void ratio.
  2. Consolidation tests predict Δh
  3. Consolidation removes water without replacing
    the water with air.
A

loaded compressible stratum

250
Q
  1. Moist sand has _________.
A

apparent cohesion

251
Q
  1. Surface tension holds the _____.
A

sand together

252
Q
  1. Loose sand when shaken will ___.
A

densify

253
Q
  1. For water filled voids, water must be expelled before _______.
A

densification

254
Q
  1. When water is expelled, pressure
    between soil grains is reduced
  2. When the pressure reduction is sufficient, the soil has no strength (like unconfined sand) or has liquefied
  3. Liquefaction can occur after earthquakes causing mudslides
A

Soil liquefaction

255
Q
  1. Cohesive strength based on
  2. Water content
  3. Plastic limit
  4. Liquid limit
  5. Stiff to hard _____ pose problems in construction
  6. Must be excavated or remediated
  7. Unsatisfactory for foundations of shoring
A

Clays

256
Q
  1. Soils are loaded in compression
  2. NATURAL so strength and properties vary as the RULE
  3. Designs and methods must change to match the soil property encountered.
A

Soil strength

257
Q

Load carrying capacity of soil is dependent on its _____.

A

shear strength

258
Q

The ability of soil to support an _____ is determined by its shear strength

A

imposed load

259
Q
  1. Made in advance of construction
  2. Assist in design of structures
  3. Subsurface exploration
  4. Made available to the contractor during estimating
    period
A

Soil exploration

260
Q
  1. Locate and define vertical and horizontal boundaries of:
    a. Various soils and rock strata
    b. Underlying the site of proposed construction
  2. Locate the groundwater table
  3. Determine engineering properties of subsurface material
A

Field exploration

261
Q

a. Preliminary examination or survey of a job site.
b. Some useful information on the area (e.g., maps or aerial photographs) will already be available
c. Astute person can learn much about surface conditions and get a general idea of subsurface conditi
ons by simply visiting the site.
d. The geotechnical engineer should then visit the site in person.
e. Observe thoroughly and carefully, and interpret what is seen.

A

1-Reconnaissance

262
Q

What are the steps of soil exploration?

A
  1. Boring
    a. Direct exploration
    b. Semi‐direct exploration
  2. Sampling
    a. Disturbed
    b. Undisturbed
  3. Testing
263
Q

Direct Exploration is Performed by visual inspection through:

A
  1. Test pits
  2. Test trenches
  3. Test holes
264
Q

Preferred when groundwater is 20’or more below the surface: Because most saturated soils will not cling sufficiently to the auger for lifting.

A

Direct Exploration

265
Q
  1. excavations into the earth t
    hat permit a direct, visual
    inspection of the soil along the sides of the pit.
  2. They may be large enough to allow a person to enter : make inspections by viewing the expos
    ed walls, taking color photographs of the soil in its natural condition, testing in situ, and taking undisturbed samples.
A

Test pits:

266
Q
  1. Press the thumb firmly into the soil in question
  2. If the thumb makes an indentation in the soil only with great difficulty, the soil is probably Type A
  3. If the thumb penetrates no further than the length of the thumbnail, it is probably Type B soil
  4. If the thumb penetrates the full length of the thumb, it is Type C soil.
A

Thumb penetration test

267
Q
  1. The _______ is subjective and is therefore the least accurate method.
  2. Used for determining shoring requirements: For deeper pits, the excavation may need to be shored to protect persons entering the pits.
A

thumb test

268
Q

Support system to hold soil back during excavation for

underground construction or exploration

A

Shoring:

269
Q
  1. Determines unconfined compressive strength of soil (qu) through penetration of soil.
  2. Direct exploration method
  3. Based on allowable pressure(psf), not density (pcf)
  4. Have error rates in the range of ±20‐40%
A

Pocket Penetrometer

270
Q

Direct exploration advantages:

A
  1. Permits observation in natural state

2. Can obtain undisturbed samples

271
Q

Direct exploration disadvantages:

A
  1. Usually depth is restricted

2. By equipment or groundwater

272
Q
  1. Auger drilling rig
  2. Drills and samples
  3. Solid Stem
  4. Hollow Stem
  5. Rotary Drilling
  6. Uses Slurry or Drilling Mud
A

Semi-direct exploration

273
Q
  1. Thin walled tube sampling
  2. Shove sample tube into bottom of boring
  3. 2‐5 in in diameter
  4. Up to 4’ in length
  5. Obtain an undisturbed sample
A

Shelby Tubes

Soils (1 decks)

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