Earth Engineering - Weathering, Erosion, & Soils

Vocabulary flashcards about weathering, erosion, and soils, based on lecture notes.

Liquefaction

Transformation of a cohesionless material from a solid state into a liquefied state as a consequence of increased pore-pressures.

Regolith

The layer of rock and mineral fragments that nearly everywhere covers the Earth’s land surface.

Soil (Geologist's View)

A combination of mineral and organic matter, water and air – that portion of the regolith that supports the growth of plants.

Soil (Engineer's View)

Any un-cemented or weakly cemented accumulation of mineral particles formed by the weathering of rocks, including the void space between particles containing water and/or air.

Horizons

Discrete zones or layers in a soil profile.

Weathering

Mechanical and chemical breakdown of rocks exposed at the earth's surface into smaller particles that may differ in composition from the original subsurface.

Erosion

The detachment and transportation of surface particles due to gravity, water, wind, glacial ice, or waves.

Fluvial Erosion

Erosion by water.

Aeolian Erosion

Erosion by wind.

Mechanical Weathering

The process by which a rock is broken into smaller and smaller pieces, each retaining the characteristics of the original material.

Chemical Weathering

The chemical transformation of rock into one or more new components.

Porosity (n)

VV / Vtotal (Void Volume / Total Volume)

Void Ratio (e)

VV / VS (Void Volume / Solid Volume)

Water Content (w)

MW / MS (Mass of Water / Mass of Solids)

Degree of Saturation (Sr)

VW / VV (Volume of Water / Volume of Voids)

Bulk Density (ρ)

Mtotal / Vtotal (Total Mass / Total Volume)

Unit Weight (γ)

Wtotal / Vtotal (Total Weight / Total Volume)

Plasticity

The ability of a soil to undergo unrecoverable deformation at constant volume without cracking or crumbling

Liquid Limit

Upper limit of water content for the soil to exhibit plastic behavior.

Plastic Limit

Lower limit of water content for the soil to exhibit plastic behavior.

Shrinkage Limit

The transition from plastic to solid behavior; no volume change with further drying.