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15 Cards in this Set
- Front
- Back
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3 Phases of a Soil Sample |
Fluid - water Gas - air Solid - soil (made of minerals or organic matter) |
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Difference between Soil and Rock |
Soil particles behave independently, i.e. grains are not attached to each other and can easily be separated (as opposed to rock) |
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What characteristics do we categorize soils based on? |
Origin, mineralogy, grain size, plasticity, density, & behaviour (response to loading in either deformation or strains, etc) |
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What are tailings |
Byproducts left over from mining and extraction of resources |
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What is a tailings pond? |
Wet storage area for tailings that allow them to be continuously submerged |
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How to differentiate organic and inorganic soils? |
Organic soils are usually found at shallow depths (removed for engineering purposes - weak) Organic soils can be identified - in laboratory (by burning out organic matter and measuring the difference in mass) - texture (fibrous, peat-decomposing plant) - smell - light weight - dark colour |
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Mineral Categories? |
Silicates, Carbonates, Clay Minerals |
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Types of Silicates? |
Quartz (SiO2) - chemically + mech. strong, most dominant mineral in earth crust (quartz sand), often light coloured with some transparency Feldspar - weaker, less common, light colour, opaque Mica (directional) - particles made of sheets, flaky, various colours, opaque, weak, compressible |
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Types of carbonates? |
Calcite - Easily soluble in rain water (acidic), most of ten founded as a cementing agent within silicates, on its own - weak + compressible, includes biogenic sands composed of exo skeleton, or bore fragments of sea creatures (this is a carbon based organic matter --> inorganic) Dolomite - soluble, and weak |
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Clay Minerals |
Kaolinite, illite, montmorillonite (highly expansive), bentonite - commonly used chips (used to backfill when swell occurs) |
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Clay Particles |
Clay particles in nature aer almost always hydrated (layers of water molecules - absorbed water), can attract or repel each other, flocculate or disperse, depends on minearlogy, and/or presence of ions in water clays are electrically sensitive --> cohesive |
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Quick Clays |
Can gave a resonably measurable strength - but with very small changes to chemistry or stress state - Can disperse |
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Leeching? |
A deposit originally under salt water, gets exposed to fresh water - the deposite undergoes structural changes |
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Cohesive vs Non-cohesive Soils? |
Most important characterstic of soils - there are also intermediate soils (silts, mixes, etc) For simplicity: clay - cohesive, sand - noncohesive/granular |
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Granular Soils? |
Determines mechanical interaction of particles SHAPE - rounded, subrounded, sub-angular, and angular (lock in together - strongest soil shape) ROUGHNESS - how rough the surface of the particle is CRUSHABILITY - how easy it is to shear the soils/deform it |
