Engineering Geology

Question 1

What are the different types of subsurface exploration?

Answer 1

Boring, test pits, trenches

Question 2

What is boring?

Answer 2

This is a cylindrical hole drilled into the ground for the purpose of investigating subsurface conditions, performing field tests, and obtaining soil, rock, or groundwater specimens for testing

Question 3

What are trenches?

Answer 3

Trenches are long and narrow excavations usually made by a backhoe or bulldozer

Question 4

What are the three types of samplers that are used to retrieve soil and rock specimens from boring?

Answer 4

California sampler

Shelby tube sampler

Standard penetration test sampler

Question 5

What are the types soil samples?

Answer 5

Altered sample

Disturbed sample

Undisturbed sample

Question 6

What is an altered sample?

Answer 6

During boring operations, soil can be altered due to mixing or contamination.

Question 7

What is a disturbed sample?

Answer 7

Disturbed soil is defined as soil that has been remolded during the sampling process.

Question 8

What is an undisturbed sample?

Answer 8

Undisturbed samples are often defined as those samples obtained by slowly pushing thin walled tubes, having sharp cutting ends and tip relief, into the soil.

Question 9

What are the three most common types of field tests that can be performed at the time of drilling?

Answer 9

Standard penetration test

Cone penetration test

Vane shear test

Question 10

What is spread footing/pad footing?

Answer 10

Spread footings are often square in plan view, are of uniform reinforced concrete thickness and are used to support a single column load located directly in the center of the footing.

Question 11

What is strip footing/wall footing?

Answer 11

Strip or wall footing is often used for load-bearing walls. They are usually long reinforced concrete members of uniform width and shallow depth.

Question 12

What is a conventional slab on grade foundation?

Answer 12

A continuous reinforced concrete foundation consisting of bearing wall footings and a slab in grade. Concrete reinforcement often consists of steel re-bar in the footings wire mesh in the concrete slab.

Question 13

What is post-tensioned slab-on-grade foundation?

Answer 13

A continuous post-tensioned concrete foundation. The post-tensioning effects is created by tensioning steel tendons or cables embedded within the concrete.

Question 14

What are driven piles?

Answer 14

Driven piles are slender members, made wood, steel, or precast concrete, that are driven into place using pile-driving equipment.

Question 15

What is a mat foundation?

Answer 15

A large and thick reinforced concrete foundation, often of uniform thickness, that is continuous and supports the entire structure.

Question 16

What are polymorphs?

Answer 16

Two or more minerals with the same chemical composition but with differing crystal structures. Example, diamond and graphite

Question 17

What is reconstructive polymorphism?

Answer 17

Polymorphic reaction that requires bond breaking and reassembly of bonds; requires lots of energy; slow; difficult to reverse. Example diamond-graphite, calcite-aragonite

Question 18

Which rock minerals dominate the earth’s crust and which chemicals make up 94.7% of crystal volume and 74.3% of crustal mass?

Answer 18

1) Silicate minerals

2) oxygen and silicon

Question 19

What are the different types borings?

Answer 19

Auger boring
Test boring
Test boring of large samples
Test boring through hollow stem auger
Rotary coring of soil or soft rock

Question 20

What is a foundation?

Answer 20

A foundation is the part o the structure that supports the weight of the structure and transmits the load to underlying soil or rock.

Question 21

What are the two basic aspects of foundation design?

Answer 21

1) Selecting the type of foundation, whether it be a deep or shallow foundation
2) developing design parameters based on the bearing capacity of the foundation.

Question 22

What are eight reasons for carrying out a site investigation?

Answer 22

1) Knowledge of the general topography of the site.
2) to locate buried utilities
3) the general geology of the area
4) the previous history of the site and use.
5) the availability and quality of local construction materials.
6

Question 23

Differentiate between structural rock mechanics and comminution

Answer 23

Structural Rick mechanics is concerned with the stability of engineering structures in which the material is predominantly rock while comminution is concerned with the reduction of rock to small fragments by the application of external forces as in drilling, blasting, cutting and grinding.

Question 24

What is the Wilson cycle?

Answer 24

A model summarizing the evolution of tectonic plates and plate interactions through geological time.

Question 25

What is liquefaction?

Answer 25

A type of ground water failure in which water saturated sediment turns from a solid to a liquid as a result of shaking, often caused by earthquake or volcanic eruption.

Question 26

What are stratigraphic laws?

Answer 26

These are basic principles that are used in deciphering spatial and temporal relationships of rock layers.

Question 27

List steno's laws of stratigraphy

Answer 27

Law of superposition Law of original horizontality Law of cross-cutting relationships Law of lateral continuity

Question 28

Explain the law of superposition and law of original horizontality

Answer 28

law of superposition- younger layers of rock sit atop older layers Law of original horizontality-layers of sedimentary rock are originally deposited flat.

Question 29

Explain the law of cross-cutting relationships and the law of lateral continuity.

Answer 29

law of cross-cutting relationships-rock layers A and B must be older than the intrusions (C) that disturbs them. law of lateral continuity-layers of rock are continuous until they counter other solid bodies that block their deposition or until they are acted upon by agents that appeared after deposition took place.

Question 30

List and explain the stratigraphic laws

Answer 30

Laws of inclusions- this states that rock fragments must be older than the rock containing the frags. Law of faunal succession- fossil groups were succeeded by other fossil groups through time. Allowing for correlation to be made around the world.

Question 31

What are the processes that cause atoms to bond together to form solids?

Answer 31

Precipitation from solution Sublimation from gases Crystallization from a melt Solid state growth Solid-liquid or solid-gas reaction

Question 32

What is the procedure and application of rotary coring?

Answer 32

Procedure- outer tube with diamond but on lower end rotated to cut annular hole in rock Application-to recover core better in fractured rock, which has less tendency for caving during core removal

Question 33

What is procedure and application of auger boring?

Answer 33

Procedure- dry hole drilled with hand or power auger and samples recovered from auger flutes Application-in soil and soft rock, to identify geologic units and water content above the water table

Question 34

What is the procedure and application of test boring?

Answer 34

Procedure-hole drilled with auger or rotary drill | Application-to identify soil or soft rock; to determine water content.

Question 35

What is the procedure and application of test boring through hollow stem auger?

Answer 35

Procedure-hole advanced by hollow stem auger Application-in gravel soils not well adapted to harder soils or soft rock.