question

Define Engineering Geology

answer

The science of geology applied to environmental and engineering concerns, including the safety and performance of man-made structures, and to public health, safety, and welfare.

question

Define Geological Engineering

answer

The engineering discipline specializing in the evaluation and design of engineering projects, in or on the earth and the evaluation of earth materials.

question

What are Geological engineers work typically involves

answer

Mining Petroleum recovery Civil engineering And deal with design and performance of the project

question

Compare a engineering geologist and geological engineer.

answer

The engineering geologist is a geologist with a strong awareness and understanding of engineering and engineering principals The geological engineer is an engineer with a string awareness and understanding of geology and geologic principals.

question

Engineering Geology includes

answer

•describing and evaluating subsurface geologic structures, stratigraphy, and water conditions affecting the things humans build; •exploring and developing rock, soil,and water resources; •evaluating natural hazards including earthquakes, landslides, floods, subsidence, radon, and asbestos; and, •participating in multidisciplinary teams.

question

Who was first hydro engineering geologist...and what were his accomplishments.

answer

William Smith *"The map that changed the world" •Canal construction •Transport of coal *Published 1815 -1817

question

What is the height and width of Natural Bridge?

answer

215 feet tall and 90 feet wide

question

What makes natural bridge unique to other bridges>

answer

only known natural arch in the world to have a highway across it -U.S. Rt 11

question

What is the thickness at of the bridge?

answer

55 feet

question

What is the historical background of Natural Bridge?

answer

*Purchased by Thomas y Jefferson in 1774 from King George III *Held by heirs until 1833 *Present owner purchased it in 1984

question

What date did a rock fall occur at Natural Bridge?

answer

Saturday Saturday October 23, 199

question

What is the engineering definition of bedrock vs. soil

answer

Bedrock- Hard durable continuous rock mass lying at or near surface which must be excavated by systematic drilling and blasting. A.K.A "Rock Borrow" Soil-Loose unconsolidated (non-lithified) material lying above the bedrock, which can be excavated by conventional means. A.K.A "Common Borrow"

question

What dose the distinction of soil effect when constructing?

answer

The Cost

question

What is the Agricultural Definitions of Soil?

answer

A= Top soil, organic, black zone of mineral leaching. B= Zone of accumulation, red/brown clays. C= Saprolite, weathered bedrock

question

The distinction between engineering "soil" and agricultural soil is NOT important when classifying them. (True/False)

answer

False

question

Define Transported soil

answer

-unlithified materials that overlie bedrock from which they were not derived?

question

Give an example of Transported Soils....

answer

Glacial, lacustrine, marine, eolian, alluvial (flood planes, terraces, deltas, fans) shoreline, gravity deposits, man-made fill, volcanic deposits and cumulose fill

question

Define Residual Soils

answer

Unlithified minerals derived from the weathering of material it overlies

question

Name 4 soil formations?

answer

1) Physical Weathering 2) Chemical Weathering 3) Hydrolysis 4 )Oxidation

question

Define Physical Weathering

answer

Mechanically breaking rock apart into smaller pieces with out chemically altering the mineral composition

question

Define Chemical Weathering

answer

Decomposition of rock by chemical reactions which alter the chemical composition of the rock forming new minerals.

question

What is Hydrolysis?

answer

Weathering reaction from contact with water, probably assisted by naturally occurring carbonic acid, Produces clay minerals (montomorillinite, kalinite, illite)

question

What is oxidation

answer

Cations from hydrolysis react with O2 to produce oxides usually red hematite.

question

What are weather processes?

answer

Not all materials weather at the same rate. Rates of weathering can be compared on the Goldich Series ( same drawing as bowmen reaction series)

question

Minerals that form early in the bowman's reaction series such as (Olivine) are most unstable and weather fastest at the earth's surfaces. (True/False)

answer

True

question

What are the five factors that affect soil development and thickness?

answer

1) Climate 2) Time 3) Vegitation 4) Topography 5) Parent Material

question

How dose one locate a soil/rock boundary?

answer

Drilling, Augering, & Coring

question

Explain 3 problems that occur when boring a hole?

answer

1. Bedrock occurs at point where soil auger refuses to advance. 2. Bedrock occurs where split-spoon sampler will not advance with blows from standard sliding hammer. 3. Bedrock occurs where shelby tube sampler cannot be hydraulically pushed farther

question

Bore holes are expensive too! (True/False)

answer

True

question

What occurs during seismic refraction?

answer

1. Shock waves travel through different materials at different velocities. Soil is lessdense than rock so velocity will also be lessin soil. essso. 2. Waves will be bent (refracted) each time they encounter a boundary between layers with different velocities

question

What are two kinds of weathered rock and the abbreviation for the names?

answer

(SWR)- Soft Weathered Rock (HR) - Hard Weathered Rock

question

Define soft weathered rock...

answer

Material that can be penetrated with some difficulty using power augers and yields SPT values >100 blows but< SPT Refusal.

question

Define hard weathered rock...

answer

Material that cannot be penetrated by power augers with great difficulty using power augers and yields SPT refusal

question

What is SPT Refusal?

answer

When the soil has less than or equal to 1 inch of penetration per 50 blows.

question

What dose an inferred rock line indicate?

answer

The the level at which augers could no longer penetrate.

question

Hard Rock Symbols are not shown when rock is cored and only to that depth cored. (True/False)

answer

False

question

What is core recovery (Rec.)?

answer

Total length of rock recovered in the core barrel divided by the total length of the core run times 100%

question

What is rock quality Designation? (ROD)

answer

The total length of sound rock segment received that are longer that or equal to 4" divide by the total length of the core run times 100%.

question

What happens during seismic refraction?

answer

1. Shock waves travel through different materials at different velocities. Soil is less dense than rock so velocity will also be less in soil. 2. Waves will be bent (refracted) each time they encounter a boundary between layers with different velocities.

question

Ware are the three primary seismic waves and what do they do?

answer

P-waves: primary, compressional, fastest S-waves: secondary, shear L-waves: last, large, slowest and do most damage during earthquakes

question

The P-wave velocities are used to calculate depth(D) to the soil/rock boundary and rippability ? (True/False)

answer

True

question

What two values do you need from seismic refraction to determine bed rock?

answer

1) STP N-Value 2) Comprehensive wave velocity (fps)

question

Resistivity is the resistance to the flow of ....

answer

an electrical current through a rock cylinder of length a and a cross-sectional area S. ρ = RS/a(for laboratory sample

question

Resistivity and Conductivity are related to....

answer

Concentrations of electrolytes in the pore spaces -Type of soil or rock a. Porous sand & gravel have high resistivity when dry. Impermeable silt and clay have low resistivities. -Location of groundwater table

question

Depths to Boundaries are found by....

answer

plotting cumulative resistivity graphs.

question

Gravity is good for locating bodies

answer

of different density in the subsurface because gravitational force will change minutely over them.

question

Give a high and low gravity example in the field.

answer

High gravity anomalies occur in dense igneous intrusions into low sedimentary rock. Low Gravity occurs in caverns and mines.

question

How is Gravity measures?

answer

in gals X 10^-3 (in honor of Galileo) or miligals

question

What is earths gravity?

answer

980 or 980,000 miligals

question

Define Magnetism

answer

A magnetometer is used to measure the earth's magnetic field plus residual magnetism in subsurface material caused by the presence of magnetic minerals.

question

The regional magnetic field is calculated and subtracted leaving only..........?

answer

The effects of residual magnetism.

question

Variations in the residual magnetism indicate underground magnetic bodies in....?

answer

Mafic igneous intrusions Sand and gravel deposits that accumulate heavy minerals.

question

How is magnetism measured?

answer

1 gamma = 10^-5 oersted

question

What is 1 oersted is magnetic force equivalent to ?

answer

1 dyne acting in the direction of the magnetic vector (force causing acceleration if 1 cm/sec^2 on 1 Gm)

question

Magnetic data provides information on

answer

~basement depth ~Unexpected relationships between the and a shallower exploration target. ~Can help define structures in detail

question

How is magnetic data best used?

answer

In as synergistic manner.

question

What other data sets is magnetic data integrated with when forming data sets?

answer

gravity, seismic, on surface and subsurface geologic information.

question

When was the first magnetic map published?

answer

1977

question

Please provide the soil classifications for the went worth scale.

answer

>2 mm....Gravel 2-1/16 mm....Sand 1/16-1/256 mm....Silt 1/256....Clay

question

Please provide the soil classifications for the Phi Scale.

answer

-2 to -1.... Gravel -1 to+3.75.... Sand +3.75 to 8.0 Silt +8.0....Clay

question

Please provide the soil classifications for the TBR Scale

answer

>2 mm....Gravel 2-.05 mm....Sand 0.05-0.005 mm....Silt <0.005....Clay

question

What dose USDA stand for?

answer

U.S. Dept. of Agriculture

question

What is the TBR ?

answer

Transportation Research Board

question

Lit the three steps used to name the soil using one of the textural classifications:

answer

1. Remove gravel and larger sizes 2. Sieve the remainder, determine percent sand, clay, and silt. 3. Locate the name on appropriate ternary diagram

question

What are the three ways a clay can be refereed too.

answer

1) Clay sometimes refers to the size of material. 2) Clay sometimes refers to particular group of phyllosilicate minerals (sheet like structure) 3) Clay sometimes refers to specific engineering properties or type of soil behavior.

question

What is the difference between TBR and USDA clay sizes?

answer

TBR = <0.005 mm USDA = <0.002 mm

question

In mineralogy clays are minerals which have?

answer

cohesion and plasticity when wet.

question

What is the chemical make up of clays?

answer

They consist of sheets of hydroxyls (Al(OH)3, Mg(OH)2) altering with silicate sheets (Si2O5)

question

What are the 3 types of clays?

answer

1) Two layer clay- Kaolinite and Halloysite 2)Three layer clay - smectite, illite, vermiculite 3) Mixed layer clay- chlorite

question

Three layer clays have the tendency to...

answer

Swell

question

Where is montomorillionite formed?

answer

Volcanic soils and ares of young sediments ex. costal planes of VA

question

Soils that form on lithified sedimentary rock tend to be ....?

answer

Non-expansive

question

Who first developed the unified soil classification system? And what was it used for?

answer

Originally developed by Arthur Casagrande for the army corps of engineers to use in air field construction.

question

Soil classification can be checked in the field by conducting what test?

answer

Atterberg Limits Test

question

How to determine if soil is Coarse or Fine?

answer

The soil is fine if >50% passes #200 sieve by weight (clay & silt) and the Coarse soil )

question

What is the diamiter if the holes in a sieve #200

answer

0.74 .. diameter

question

G=

answer

Gravel

question

S=

answer

Sand

question

M=

answer

Silt

question

C=

answer

Clay

question

o=

answer

Organics

question

Pt=

answer

Peat

question

W=

answer

Well graded (all sizes represented)

question

P=

answer

Poorly Graded

question

H=

answer

High Plasticity

question

L=

answer

Low Plasticity

question

GW=

answer

Well graded gravel

question

GP=

answer

Poorly graded gravel

question

SM=

answer

Silty Sand

question

ML=

answer

Low Plasticity Silt

question

CL=

answer

Low plasticity clay

question

MH=

answer

high plasticity silt

question

CH=

answer

High plasticity clay

question

Explain clays, silts, and sands in reference to cohesion?

answer

Clays have cohesion Silt have little to no cohesion Sand has no cohesion

question

Soils that form on ithified sedimentay rock tend to be ....?

answer

Non-expansive

question

What are three steps when determining classification of soil?

answer

1) Examine the soil 2) Examine grain size 3) Size Distribution Diagram

question

What is Effective Size D10

answer

The size for which 10% of soil is finer and can approximate soil permeability

question

Are uniform soils more permeable than non- uniform soils?

answer

True

question

What percentage must pass through a 200 # sieve to identify it as coarse. And what type of soil is it?

answer

50% or less---gravel or sand

question

What percentage must pass through a 200 # sieve to identify it as fine. And what type of soil is it?

answer

Greater than 50% --- silt of clay

question

What are the four consistencies that soil must pass through when drying?

answer

1) Liquid- flows 2) Plastic- can be deformed without cracking 3)Semi-Solid- cracks a little 4) Solid- brittle, breaks under pressure

question

What is the Atterberg limits ?

answer

Are the water contents (w%) of the soil as it changes from one consistency to the next.

question

Water content in percent is equivalent to ...

answer

(mass water /mass solids)*100

question

What is the liquid limit device?

answer

The liquid limit device determines LL by jarring a moist sample and observing closure of a groove in the soil. (LL= water content when grove 13 mm wide closes in exactly 25 blows of the cup.)

question

What dose LL stand for?

answer

Liquid Limit- The water content of the soil when just between a liquid and a plastic consistency.

question

What dose PL stand for?

answer

Plastic Limit- The water content of the soil when just between plastic and solid in consistency.

question

Who created the plasticity charts?

answer

Cassagrande

question

Plasticity chart can help you find the

answer

liquid limit & plasticity chart

question

What dose high PI/ Plasticity Index indicate?

answer

More compressieve soil

question

What is the equation for plasticity index?

answer

LL-PL=PI

question

Any soil sample can be thought of as containing _______ possible phases.

answer

Three possible phases

question

What are the soil phase of a soil phase diagram?

answer

Air, Water, Solids

question

What is the geological definition of Compaction?

answer

Reduction in volume that occurs under the load of overlying sediment as part of the sedimentary process. (Includes both engineering compaction and consolidation)

question

What is the geological definition for consolidation ?

answer

Lithification, total process by which sediment becomes rock. (Includes geologic compaction and cementation)

question

What is the goal of soil compaction?

answer

To decrease the void ratio and permeability.

question

What is the engineering definition of compaction ?

answer

Reduction of volume by rearrangement of particles without the outflow of water involved or required.

question

What is the definition of engineering consolidation?

answer

Reduction of volume caused by the outflow of water as load is transfered from the water to the soil particles. ( This process is time related and takes longer than compaction)

question

At what depth are the layer of lift during compaction?

answer

(6-12inches)

question

What three tools are the lift layers compacted by?

answer

Vibrating rollers (cohesion-less soils-sandy) Sheep's foot roller (cohesive soil - clayey) Hand held tampers.

question

What is a controlled earth fill?

answer

A fill in which the materials are carefully controlled. Not allowing rocks bigger than a foot in diameter, excess water content, also no tree content or organic soils.

question

What is the case history for Blacksburg High School?

answer

The school was built on half bed-rock and half fill dirt. Most-likely the fill dirt was not controlled and contained organic materials. There was significant foundation problems, including water damage through the cracks in the foundation. Officials were worried about water seeping into the electrical system.

question

What is the case history of East-side H.S. in Rockingham County Virginia?

answer

The foundation was partially built on a Limestone deposit and the rest was constructed on fill dirt. The was post the Blacksburg high school issue and they wanted to avoid a total structural loss; and got the problem corrected.

question

What is the case history for Radford?

answer

Radford is built on set of old river terrace deposits, projecting toward flood planes; in some area there is 30 feet of fill which was supposed to be controlled. Instead there were large trees, boulders, and washing machines thrown in for compaction. Some areas experienced sinking of parking lots ect.

question

What are two methods of compaction testing?

answer

1) Proctor testing 2) Field Density Testing

question

Define proctor testing?

answer

of samples in lab to determining the optimum unit weight and moisture content to get densest soil for a given compactive effort. (A measure of the energy put into the compaction)

question

What is field density testing?

answer

is conducted during construction to ensure that the soils are properly compacted according to Proctor Test results.

question

In the proctor test curve what happens if the soil is compacted too dry?

answer

The fill may be less flexible causing cracking and will result in piping (internal erosion of the fill)

question

In the proctor test what happens if the soil is too wet?

answer

The fill may be to flexible and not as strong.

question

What are the effect of water on Silty soils, and Clayey Soils?

answer

Silty - Usually dry out quickly and need to be kept wet with water trucks. Clayey - They are usually too wet in the field and need to be spread out and dried.

question

What is the modified proctor test?

answer

Uses same size mold, compact in 5 lifts instead of 3, Uses a 10 lb. hammer, 25 blows per lift, and the hammer falls 18 inches instead of 12. The compactive effort is about 4.5X that of the standard effort.

question

What are the benefits of a modified proctor test ?

answer

Denser fill greater strength Less Moisture

question

What soils must be used to complete a proctor test?

answer

Cohesive Soils (clays and moist silts)

question

What soils must be used in a relative density test?

answer

cohesionless soils (sands)

question

What happens to cohesionless soils during earthquakes?

answer

Liquification of fine sand and silt with low relative density and high ground water table.

question

What is liquification?

answer

the loss of bearing capacity of a soil caused by vibrations.

question

What happens to the pore space when vibrations occur?

answer

Vibrations increase the pressure within water in the pore space. This decreases the pressure between individual grains .

question

What is effective stress?

answer

A decrease in pressure between individual grains and controls soil strength.

question

What are three methods of measuring Field Density and Moisture Content?

answer

1) Sand Cone 2) Speedy Moisture Meter 3)Nuclear Density Gages

question

What is the Sand Cone device?

answer

A device for measuring the volume of a hole from which the soil has been remove by filling the hole with sand of a known density and determining the weight of the sand required to do so . From the volume of the hole and the weight of the soil removed can be found the soil density.

question

What is stress?

answer

An internal condition within a substance caused by an external pressure. (force acting over a specified area)

question

What are three types of Stress?

answer

Compressive, Tensile, Shear

question

What is compressive stress

answer

Compression refers to a set of stresses directed toward the center of a rock mass. The compresive strength refers to the maximum stress applied before failure.

question

What is tensile stress?

answer

A stress which stress rock in two opposite directions.

question

What is shear stress ?

answer

A stress component parallel to a given surface such as a fault plan that results from forces applied parallel to the surface or from remote forces transmitted through the surrounding rock.

question

What is strain?

answer

Deformation of a substance as a result of stress.

question

What is strength?

answer

The Maximum stress that can be applied to a substance before it fails.

question

What is failure?

answer

Excess strain in a substance that could cause a rupture or plastic deformation beyond allowable limits.

question

What is total stress

answer

Stress in a soil resulting from the weight of overlying soil and water

question

What is neutral stress

answer

Water pressure within a soil that acts to puch soil grains apart.

question

What is effective stress?

answer

Stress withing the soil particals in the soil it equals total minus neutral stress.

question

Effective stress controls?

answer

The strength of a soil.

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