McCarthy - Geotechnical Engineering Chapter 2

Soil

the accumulation of particles of disintegrated rock and also human made materials.

Coarse-grained soil

Gravel and Sand are universally considered this type of soil for the individual particles are large enough to be distinguished without magnification.

Fine-grained soil

Silts and clay are considered this type of soil because of their small particles—too small, for the most part, to be seen unaided.

Cobbles or Boulders

Particles larger than gravel

Clay Soil

plastic over a range of water content; that is, the soil can be remolded or deformed without causing cracking, breaking, or change in volume, and will retain the remolded shape.

Silt Soil

possesses little or no plasticity and, when dried, has little strength.

Dilatancy

If a small sample of moist silt is shaken easily but rapidly in the palm of the hand, water will appear on the surface of the sample but disappear when the shaking stops.