This document discusses key geotechnical properties of soils including mechanical strength, moisture content, moisture movement, and plasticity. It defines plasticity in terms of liquid limit, plastic limit, and shrinkage limit. Graphs are provided showing the relationships between these properties. The document also discusses cation exchange capacity and its importance for soil fertility. Finally, it outlines some applications of understanding geotechnical properties in fields like geological science, civil engineering, material science, and soil science.

2.  GEOTECHNICAL PROPERTIES
 PRINCIPLES
 APPLICATIONS

3.  MECHANICAL STRENGTH : This is normally measured in
terms of resistance to shear, which is a function of the
internal friction and cohesion of the soil
 SOIL MOISTURE CONTENT : When a soil has completed
its free drainage under the action of gravity , it retains
a certain amount of water at a reduced pressure in the
pores and on the surfaces of particles by virtue of the
surface tension and adhesive forces.

4.  MOISTURE MOVEMENT : in the case of saturated flow
in the liquid phase, the permeability or rate of
moisture movement in a soil decreases with increasing
clay content due to increasing proportion of small
capillary channels
 PLASTICITY : This occur when the moisture contents of
the soil as it passes from one state to the next s a wet
slurry of remoulded clay soils dries , it passes through
a series of states, that is liquid ,plastic , semi solid and
solid .

5. Fig 1: Showing the Plasticity range

6.  PLASTICITY
it is defined as a function of
Liquid limit
Plastic limit
Shrinkage limit

7. FIG 2 : GRAPH SHOWING LIQUID LIMIT

8.  This is the water content at which soil ceases
to be entirely plastic and becomes a semi
plastic solid
FIG 2. GRAPH SHOWING PLASTIC LIMIT

9.  This is the water content below which further
loss of moisture does not result in a
decrease in the soil volume
FIG 3 : GRAPH SHOWING SHRINKAGE LIMIT

11.  Refers to cation exchange capacity
 Ability to retained supply nutrient
 Fertility
 HIGH ACTIVITY CLAYS
 Less weathered , high effective surface area
 Smectite , vermiculite , mica ( illite ) , chlorite
 LOW WEATHERED CLAYS
 More weathered , low effective surface area
 kaolinite

14.  GEOLOGICAL SCIENCE
Understanding of geological environments, economic
geology, environmental geology, engineering geology
 CIVIL ENGINEERING
understanding the soil properties, soil behaviour,
foundation and slope stability .
 MATERIAL SCIENCE
understanding the material properties , manufacturing
 SOIL SCIENCE
Soil stability , agriculture