SOIL MECHANICS [For DBATU – Semester 5 – Civil Engg]

SYLLABUS

Module I : Introduction                                                                                                                              (6 Lectures)

Definition of soil and soil engineering, Application areas of soil mechanics, Three Phase soil system, Soil moisture, Index properties of soil: Different unit weights of soil, and their determination, unit weight of solids, unit weights of soil mass viz. saturated unit weight, Submerged unit weight, dry unit weight, method for determination of field density viz. sand replacement and core cutter, Specific Gravity determination methods void ratio and porosity, degree of saturation, Inter relation between weight volume state, density indexes

Module II : Soil Consistency                                                                                                                       (6 Lectures)

Atterberg’s limits and their significance, Soil Classification: Soil classification based on particle size and constituency, I.S. classification system of soils. Soil structure and fabric, Effective Stress Concept: Terzaghi’s effective stress concept, equilibrium water content, frost action

Module III : Flow of Water Through Soil: Permeability                                                                               (6 Lectures)

Head, gradient and potential, Darcy’s law,  Factors affecting permeability, Field and Laboratory methods of determining permeability, Seepage pressure, quick sand condition, Derivation of Laplace equation, Flow net, it’s characteristics, it’s application, construction of flow net, piping phenomenon

Module IV : Shear Strength                                                                                                                        (7 Lectures)

Concept of shear, Coulomb’s theory and failure envelope, Principle stress, stress analysis (Total stress approach and effective stress approach), representation of stresses on Mohr’s circle for different types of soil such as cohesive and cohesionless, saturated and partly saturated soil etc, Application of shear stress parameters in the field, Different types of shear tests: Unconsolidated undrained, Consolidated undrained and consolidated drained choice of the type of test, box shear test, triaxial compression test with pore pressure and volume change measurement, Unconfined compression test, vane shear test

Module V : Compaction                                                                                                                             (5 Lectures)

Theory of compaction, factors influencing compaction, compacted density, Laboratory Standard and modified compaction test, Method and measurement of field compaction, Field compaction control

Module VI : Compressibility and Consolidation                                                                                         (6 Lectures)

Compressibility: Definition, compressibility of laterally confined soil, compression of sand and clay, e-p and e-log p curve, compression index.

Consolidation: Terzaghi’s theory of one dimensional consolidation, consolidation test, determination of coefficient of consolidation, degree of consolidation, relevance of one dimensional consolidation to field condition, time factor.