Geotechnical Design Process Flashcards
What is “till”?
Soil with a more fine-grained range of sizes that was compacted by glaciers. Typically excellent for building on, but not always.
Define Alluvial/Fluvial soil
Soil carried by rivers. The horizons reveals floods (coarse) and calm periods (fine)
What is the name for soil placed by gravity?
Colluvial
What is Aeolian soil?
Soil moved by wind (such as dunes)
What is the name for soil deposited by lakes?
Lacustrine
What is rock weathering?
The breaking down of rocks into soil
What is erosion?
The transportation of rocks and soils
What is a Phase-Diagram?
A representation of a soil sample in the three phases (air, water, and solid)
What is Geology?
The science of soils, rocks, minerals and underground water. Geology is typically not concerned with the design process.
What is residual soil?
Soil that stays in place from weathered rocks, typically found in warm climates
What are the three sources of soil?
Volcanic eruptions, decomposing organics & rock weathering
What is the first step in geotechnical design?
A desktop survey to looks at the site’s geology. This allows for an initial estimate of the design and an educated guess as to what types of tests to perform.
What is auger drilling?
A large drill that can go down at 5’ intervals. Samples or bearing tests are performed at the desired depths.
What is sonic drilling?
A vibrating drill (up to 150Hz) that collects a sample. The edges of the sample are loosened. Faster but more expensive than the auger.
What are “in-situ” tests and some examples?
A test done in the field.
- Standard Penetration test (SPT)
- Cone Penetration Test (CPT)
- Drop Cone Penetration Test (DCPT)
- Field vane
