Geotechnical Engineering

Introduction and Index Properties. 

a) Introduction to Geo-technical Engineering and its applications to Civil Engineering, Complexity of soil structure, major soil deposits of India, Field identification of soils. Introduction to soil exploration-objective and purpose. 

b) Three phase soil system, weight -volume relationships, Index properties of soil–methods of determination and their significance. IS and Unified Soil classification systems. 

Permeability and Seepage. 

a)Soil water, permeability definition and and necessity of its study, Darcy’s law, factors affecting permeability. Laboratory measurement of permeability – Constant head method and Falling head method as per IS 2720. Field test for determination of permeability- Pumping in test and Pumping out test as per IS 5529 part-I. Permeability of stratified soil deposits. 

b) Seepage and Seepage Pressure, quick sand phenomenon, critical hydraulic gradient, General flow equation for 2-D flow (Laplace equation), Flow Net, properties and application, Flow Net construction for flow under sheet pile and earthen dam.  

Compaction and Stress Distribution 

a) Compaction- Introduction, compaction tests- Standard Proctor test, Modified Proctor test, Zero air void line. Factors affecting compaction. Effect of compaction on soil properties. Field compaction methods and compaction equipment for different types of soil, Placement water content, Field compaction control- use of compaction test result, Proctor needle in field compaction control. 

b) Stress Distribution in Soils: Geo static stress, Boussinesq’s theory with assumptions for point load and circular load. Pressure Distribution diagram on a horizontal and vertical plane, Pressure bulb and its significance. Westergaard’s theory, equivalent point load method, Approximate stress distribution method.

Shear Strength of Soil 

a) Introduction- Shear strength an Engineering Property. Mohr’s stress circle, Mohr-Coulomb failure theory. The effective stress principle- Total stress, effective stress and neutral stress / pore water pressure. Peak and Residual shear strength, factors affecting shear strength. Stress-strain behavior of sands and clay. 

b) Measurement of Shear Strength- Direct Shear test, Triaxial Compression test, Unconfined Compression test, Vane Shear test. Their suitability for different types of soils, advantages and disadvantages. Different drainage conditions for shear tests. Sensitivity and thixotropy of cohesive soils. 

Earth Pressure. 

a) Earth Pressure- Introduction, Rankine’s state of Plastic Equilibrium in soils- Active and Passive states due to wall movement, Earth Pressureat rest. Rankine’s Theory- Earth pressure on Retaining wall due to submerged backfill, 

b) Backfill with uniform surcharge, backfill with sloping surface, layered backfill. Coulomb’s Wedge theory. Rebhann’s and Culmann’s graphical method of determination of earth pressure.

Stability of Slopes and Introduction to Geo-environmental engineering 

a) Stability of Slopes- Classification of slopes and their modes of failure, Taylor’s stability number, Infinite Slopes in cohesive and cohesion less soil, Landslides- Causes and remedial measures. 

b) Introduction to Geo environmental engineering, subsurface contamination, contaminant transport, effects of subsurface contamination, Control and remediation, Soil- A Geo-chemical trap, detection of polluted zones, Monitoring effectiveness of designed facilities.