Study of Soil properties

Properties Of Soil

Soil is a complex material produced by the weathering of solid rock. Weathering is caused by the agent such as temperature change, impact, flowing water, ice, wind, plants and animal. Weathering (disintegration) may be of physical or chemical. Due to physical weathering of rocks, cohesion less soil (sand, gravel, boulder) is formed.

Chemical weathering may be caused due to oxidation , hydration, carbonation etc. Clay minerals (cohesive soil) are produced by chemical weathering.

    The various agencies are of transporting and redepositing soils are water, ice, wind, and gravity. In soil mechanics we study behavior of soil under different condition, which are made with the engineering practice.

Soil Mechanics is that branch of civil engineering where we study about the application of laws of mechanics and hydraulic to engineering problems dealing with sediments and chemical disintegration of rocks.

Scope, Purpose and uses of soil mechanics  

Soil mechanics is useful in the following problem in civil engineering

1. Foundation design and Construction :- Every structure like building, bridge, dam or canal is founded in or on the surface of the earth. It is therefore necessary to know the bearing capacity of the soil and stress distribution in the soil, settlement of the foundation, effect of ground water etc.  The stability of various types of foundation depends upon the types of soil  strata, the magnitude of loads and ground water condition.
2. Design Of Earth Dam :- Since soil is used as the only construction material in an earthen dam. Therefore the construction of an earthen dam requires a very through knowledge whole of the soil mechanics.
3. Design Of Retaining  wall :- A knowledge of earth pressure is essential to design properly a retaining wall. Earth pressure is dependent on following factors;

Angle of repose(θ)
Unit weight of soil (ϒ
Height of retaining wall (H)

The magnitude of earth pressure is found out with the help of rankine’s theory of earth pressure.

Design Of Embankment and Excavation :- To design the slop and height of the embankment  or depth of excavation, a thorough knowledge of shear strength and problems of soil is essential. Design of canal required through study of seepage through embankment which was suggested by Dr. Darcy.

Pavement Design: - The thickness of pavement depends upon characteristics of sub-soil on busy pavement (highway and runway) where the intensity of traffic is very high. The effected repetition of loading and the consequence fatigue  failure has to be taken into account. A knowledge of the technique for improvement of the soil properties such as strength and stability is very much helpful in constructing pavement on poor soil.