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Basic Geotechnical Engineering

Origin of soil 

Particle  Size Classification 

Particles Size Distribution Curve  ?

Use Of Particle Size Distribution curve. 

Consistency  Limits 

Define Liquid limits, plastic limit, shrinkage limit, plasticity index, Liquidity index, consistency index, Toughness index.

Different between consistency limits and Relative density ?

Consistency Limits  Relative Density 

Applicable for cohesive soils

  Applicable for cohesionless soils
Denotes degree of firmness Denotes degree of compaction 
Function of water content  Function of void ratio 

 

Types of soil structure  Or  soil Fabric 

Diffused  Double  Layer  (DDL) ?

Clay  Minerals 

compaction of Soils 

Light Compaction Test (Standard proctor Test )

Factors Affecting Compaction 

Effect of compaction on soil properties 

Proctor Needle Method 

Field compaction Equipment 

Compaction for Deeper Layers of soils 

Permeability  and coefficient of Permeability 

Permeability 

       Permeability is defined at the property   of a material containing  continuously connected pores which  permits fluids to percolate it.

   Coefficient of permeability 

           Coefficient of permeability is defined as the average Velocity of flow that will occur through the total cross-section area of soil under unit hydraulic gradient. 

         

Constant head permeability test 

Falling head permeability test 

Pumping out test in unconfined aquifer 

Pumping out test in confined aquifer 

Factors Affecting permeability ?

Factors Affecting the rate of consolidation  ?

Spring Analogy 

Square root of tome fitting method 

Logarithm of  time fitting method 

Advantage and Limitations of direct shear test  ?

Advantage of direct shear test  

  1. The direct shear test is a simple test and relatively fast especially for granular soils .
  2. The basic principle is easily understood which can be extended to gravelly soils and other materials containing large particles. 
  3. The apparatus is relatively cheap.
  4. It is not difficult to prepare recompacted test samples. 

Limitations of direct shear test 

  1. It is difficult to control the drainage conditions if an undrained test is conducted.
  2. The stress conditions across the soil samples are very complex. 
  3. The plane of shear failure is predetermined and may not necessarily be the weakest one.
  4. There is an effect of lateral restraint by the side walls of the shear box.

Mohr's Stress Circle  

Factors Affecting Shear Strength of Cohesion Less Soil  ?

Factors Affecting Shear Strength of Cohesive  Soil  ?

Direct  or Box  Shear Test  ?

Comparison between Direct shear test and Triaxial Shear test  ?

SI.NO. Direct shear test  Triaxial shear test 
 1. Direct shear test is the simplest and oldest test. Triaxial test is much more complicated. 
 2. It is difficult to control the drainage condition.  Drainage condition during the test can be controlled. 
 3.  Pore water pressure cannot be measured.  Pore water pressure can be measured. 
 4. The shear failure is predetermined  shear failure is not predetermined 
 5. Only total stresses are known.  Effective stress can also be determined. 
 6.  Stress distribution on the failure plane is non-uniform  Stress distribution on the failure plane is uniform.