Lecture 10 - Soil origins and classifications

Question 1

Soils vs Rock

Answer 1

Both are natural aggregate of mineral grains. Soil aggregates separated by mechanical means, rock aggregate minerals connected by strong forces

Question 2

What are soils product of?

Answer 2

Rock weathering

Question 3

Soil classification

Answer 3

Gravel, sand, silt, clay

Question 4

3 phases of soil?

Answer 4

Solid (soil grains), liquid (usually water), gas (usually air)= complex behavior

Question 5

Engineering properties of soil?

Answer 5

Is a frictional material, depends on confining stress (volume change during shearing), generally no tensile strength

Question 6

What type of behavior does soil exhibit?

Answer 6

Non-linear plastic behavior,

Time-dependent behavior (consolidation, rate of shearing, strength recovery)

Question 7

Why does soil have a high uncertainty in behavior?

Answer 7

Natural material - every soil different and huge range of properties (permeability)

Question 8

What are the geo-technical challenges?

Answer 8

Consolidation settlement
Strength (bearing capacity and slop stability)
Seepage (how water flows thru soil)
Liquefaction

Question 9

What is residual soil?

Answer 9

Product of rock weathering and remain in place

Question 10

What is transported soil and how is it transported?

Answer 10

Transported to other locations by water wind volcanic eruption glacia

Question 11

What are the origins of soil?

Answer 11

Weathering, organic (eg peat)

Question 12

What is the soil formation process?

Answer 12

Residual soil -> transport by stream/river -> delta deposits -> re deposition in layers in lack/ocean -> Sedimentary soil (tectonic movement raises above sea level)

Question 13

What is a river delta?

Answer 13

Landform that forms from deposition of sediment carried by a river as the flow leaves its mouth and enters slower-moving or stagnant water