SOIL MECHANICS


(a)  Introduction: Definition of soil, rock, soil mechanics and foundation engineering, soil formation, soil structure, soil map 
of India. 
(i)  Soil properties: Basic definitions, phase diagram, water content, specific gravity, void ratio, porosity, unit weight, weight volume relationships, index properties of soil and their determination, classification of soils, degree of saturation, density index. Permeability and seepage : Darcy’s law and its validity,  seepage velocity, discharge velocity, constant      
and variable head permea‐meter, pumping in and out tests, permeability of stratified soils, factors affecting permeability, Laplace’s equation, flow potential flow net and its properties, different methods of drawing flownets, seepage pressure, quick sand, exit gradient, piping, design of filter, principle of total and effective stresses, capillarity conditions                  
in soil, effective  and pore pressures. 5 
(ii)  Stresses in soils: Need for finding stress distribution in soil, assumptions in elastic theories, Boussinesq’s equation for point, line, circular and rectangular loads, Westergaad’s formula for point load, comparison of Boussinesq’s and Westergaad’s equation, concept and use of pressure  bulbs, principle and use of New mark’s influence chart, contact 
pressure. 
(iii)  Compaction: Mechanism of compaction, objective of compaction, measurement of compaction, factors affecting compaction, optimum moisture content, Standard Proctor test, Modified Proctor test, effect of moisture content and compactive effort on dry density, zero air void curve, compaction of cohesionless soils, field compaction, field control of compaction. 
(iv)  Consolidation: Mechanism of consolidation, e‐log (p) curves, basic definitions, estimation of preconsolidation pressure, normally consolidation and over consolidation ratio, Terzaghi’s theory of one dimensional consolidation, assumptions, governing equation, standard solution, laboratory determination of consolidation properties of soil, magnitude and rate of consolidation, settlements, secondary consolidation, compression characteristics of clays  and settlement analysis. 
(v)  Shear strength : Normal, shear and principal stresses, Columb’s equation, Mohr’s stress circle, Mohr‐Columb failure criteria, laboratory determination of shear parameters of soil by direct shear tests, triaxial test, unconfined compression test, Vane shear test, Consolidated drained, consolidated undrained and unconsolidated undrained shear test, pore pressure parameters, Lambe’s p‐q diagram. 
(aa) Determination of water content by oven drying method 
(ab) Determination of specific gravity by pycnometer 
(ac) Determination of field density and dry unit weight by core cutter method 
(ad) Determination of field density by sand replacement method 
(ae) Determination of grain size distribution by sieve analysis 
(af) Determination of grain size distribution by hydrometer analysis 6 
(ag) Determination of liquid limit of soil 
(ah) Determination of plastic limit of soil 
(aj)  Determination of compaction properties of soil by standard proctor test 
(ak) Determination of shear parameters of soil by direct shear method

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