Total stress, pore water pressure, effective stress,Unit-2, Geotechnical engineering

 Total stress:- 

When a load is applied to soil, it is carried by the soil grains and the water in the pores.
The total vertical stress acting at a point below the ground surface is due to the weight of every thing that lies above including soil water and surface loading.
Vertical total stress at height  h,
Total stress
Total stress thus increasing with height and with unit weight.

Pore water pressure:-

Pore water pressure is the pressure due to pore water filling the voids of the soil. Thus
Pore water pressure

pore water pressure is also known as natural pressure or natural stress , because it can't resist shear stress.

Effective stress:- 

The effective stress at a point in the soil mass is equal to the total stress minus the pore water pressure. Thus
Effective stress

For saturated soil , it is obtained as 
Effective stress


           Gkgautam6036.blogspot.com


Comments

Post a Comment

Popular posts from this blog

What is castiglious I and II theorem and it's applications 2021

Image
Castiglious I theorem:- If the material is linearly elastic,supports are unyielding and temperature is constant,Then the first partial derivative of total strain energy with respect to the diflection/slope will give the load/moment at that point.      Derivative of total strain energy w.r.t diflection Derivative of total strain energy w.r.t slope Where:- U= strain energy P= load M= moment ∆= diflection   θ    = slope Assumptions:- 1. Material is linearly elastic 2. supports are unyielding   3. temperature is constant  Castiglious II theorem:- The  The first partial derivative of the total strain energy w.r.t. the load/ moment will give the diflection/ slope    first partial derivative of the total strain energy w.r.t. the load/ moment will give the diflection/ slope  Derivative of total strain energy w.r.t load Derivative of total strain energy w.r.t moment
Read more

Kaolinite, illite, montmorilonite, How the clay minerals kaolinite, illite and montmorillonite are formed by schematic diagram.

Image
 Kaolinite:- Kaolinite is the most common minerals of the kaolinite group of clay minerals. Its basic structural unit consists of gibbsite  sheet with aluminium atoms at the center. It is joined to silica sheet through the unbalanced oxygen atoms at the apexes of silica sheet. The total thickness of the basic structural unit is about 7 angstrom. The basic structural unit of kaolinite minerals is symbolised as shown in figure. Kaolinite minerals The basic structural units of kaolinite minerals are joined together by hydrogen bond. It develops between the oxygen atoms of silica sheet and the hydroxyls of gibbsite sheet. Since the hydrogen bond is fairly strong, it is extremely difficult to separate the layers, and hence, kaolinite minerals is relatively stable. Moreover, water cannot penetrate through the layers of the structural units of kaolinite minerals. Kaolinite shows relatively little swell on wetting. China clay is almost pure Kaolinite. Montmorillonite Montmorillonite is the mos
Read more

Bettie's law (Rayleigh theorem),What is Bettie's law? 2021

Image
  Bettie's law (Rayleigh      theorem):- When material is linearly elastic, supports are unyielding and temperature is constant Then the virtual work done by P-system of forces in going through displacement caused by Q-system of forces is equal to the virtual work done by Q-system of forces in going through displacement caused by P-system of forces. Limitations :- 1.material is linearly elastic 2.temperature is constant 3.supports are unyielding Example:- Special cases for Bettie's law:- Case -1 :- If theta-1 be the rotational displacement in the direction of M1 caused by  M2 and theta-2 be the rotational displacement in the direction of M1 caused by M1.
Read more