Engineering Properties of Soil

The basic engineering properties of the soil are
1. VOID RATIO AND POROSITY:- The component grains of soil are seldom thoroughly packed. In most cases there are always some open spaces or voids between them. The total volume of voids is of considerable significance in the determination of engineering properties of soils. The void ratio is defined as ratio between the volume of voids and volume of soil particles in a given soil mass.     
                                                  Porosity of the soil mass is the ratio between the total volume of the voids and the volume of the soil mass.    
2. PERMEABILITY:-   It has been defined as the capacity of soil to transmit water through it. permeability is one of the most important physical characteristics of the soil. It is important in the design of dams , dikes, and embankments on or passing through the soil.

3. SHEARING STRENGTH:- It is defined as the resistance of the soils to shearing forces and is regarded as one of the most important engineering properties of the soils. It is the net result of the qualitative characters of the soil, such as
a. The frictional resistance existing between the solid components of the solid components of the soil
b. The degree of cohesion and adhesion between the soil particles
c. The textural arrangement of the soil particles such as degree of interlocking,etc.
4. SOIL COMPRESSABILITY:-Many natural soils undergo considerable deformation when loaded from above. This deformation commonly takes the shape of a decrease in volume in vertical direction which may be due to
a. expulsion of air or water from within the soil
b. collapse of soil particles by closure of voids
c. deformation of solid particles
          the net result to this compression is called consolidation of soils which takes place at variable rate with time.
5. BEARING CAPACITY:- It may be defined as the capacity of a soil to withstand building loads without undergoing excessive settlement  or shear failure. Hence, this forms most important field property that needs firm evaluation before any construction programme is proposed over a soil. in practice ultimate bearing capacity is determined by loading the soils to be tested through contact plates and observation of settlement. From this allowable bearing capacity is determine for design purpose.conventionally for ordinary building construction in a planned residential colony local building codes are prepared and followed in a general way with respect to bearing capacity. For major construction, such as multistoreyed buildings and industrial buildings eloborate test are carried out to arrive at safe values of allowable bearing capacity.