Engineering Geology Flashcards
What are the different types of subsurface exploration?
Boring, test pits, trenches
What is boring?
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
What are trenches?
Trenches are long and narrow excavations usually made by a backhoe or bulldozer
What are the three types of samplers that are used to retrieve soil and rock specimens from boring?
California sampler
Shelby tube sampler
Standard penetration test sampler
What are the types soil samples?
Altered sample
Disturbed sample
Undisturbed sample
What is an altered sample?
During boring operations, soil can be altered due to mixing or contamination.
What is a disturbed sample?
Disturbed soil is defined as soil that has been remolded during the sampling process.
What is an undisturbed sample?
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.
What are the three most common types of field tests that can be performed at the time of drilling?
Standard penetration test
Cone penetration test
Vane shear test
What is spread footing/pad footing?
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.
What is strip footing/wall footing?
Strip or wall footing is often used for load-bearing walls. They are usually long reinforced concrete members of uniform width and shallow depth.
What is a conventional slab on grade foundation?
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.
What is post-tensioned slab-on-grade foundation?
A continuous post-tensioned concrete foundation. The post-tensioning effects is created by tensioning steel tendons or cables embedded within the concrete.
What are driven piles?
Driven piles are slender members, made wood, steel, or precast concrete, that are driven into place using pile-driving equipment.
What is a mat foundation?
A large and thick reinforced concrete foundation, often of uniform thickness, that is continuous and supports the entire structure.
What are polymorphs?
Two or more minerals with the same chemical composition but with differing crystal structures. Example, diamond and graphite
What is reconstructive polymorphism?
Polymorphic reaction that requires bond breaking and reassembly of bonds; requires lots of energy; slow; difficult to reverse. Example diamond-graphite, calcite-aragonite
Which rock minerals dominate the earth’s crust and which chemicals make up 94.7% of crystal volume and 74.3% of crustal mass?
1) Silicate minerals
2) oxygen and silicon
What are the different types borings?
Auger boring Test boring Test boring of large samples Test boring through hollow stem auger Rotary coring of soil or soft rock
What is a foundation?
A foundation is the part o the structure that supports the weight of the structure and transmits the load to underlying soil or rock.
What are the two basic aspects of foundation design?
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.
What are eight reasons for carrying out a site investigation?
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
Differentiate between structural rock mechanics and comminution
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.
What is the Wilson cycle?
A model summarizing the evolution of tectonic plates and plate interactions through geological time.
What is liquefaction?
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.
What are stratigraphic laws?
These are basic principles that are used in deciphering spatial and temporal relationships of rock layers.
List steno’s laws of stratigraphy
Law of superposition
Law of original horizontality
Law of cross-cutting relationships
Law of lateral continuity
Explain the law of superposition and law of original horizontality
law of superposition- younger layers of rock sit atop older layers
Law of original horizontality-layers of sedimentary rock are originally deposited flat.
Explain the law of cross-cutting relationships and the law of lateral continuity.
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.
List and explain the stratigraphic laws
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.
What are the processes that cause atoms to bond together to form solids?
Precipitation from solution
Sublimation from gases
Crystallization from a melt
Solid state growth
Solid-liquid or solid-gas reaction
What is the procedure and application of rotary coring?
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
What is procedure and application of auger boring?
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
What is the procedure and application of test boring?
Procedure-hole drilled with auger or rotary drill
Application-to identify soil or soft rock; to determine water content.
What is the procedure and application of test boring through hollow stem auger?
Procedure-hole advanced by hollow stem auger
Application-in gravel soils not well adapted to harder soils or soft rock.
