About the Book

Soil Mechanics and Foundation Engineering has seen unprecedented growth over the last few decades both in terms of knowledge and practice as well as in its significance in civil engineering profession. Over 1300 numerical and objective questions with solutions have been included in the book. Questions from competitive exams such as GATE, IES, IAS, IFS, etc., involve some of the subtle and fine concepts of the subject and their practical application, which cannot be gained by simple reading of the subject. Keeping this in view, about 600 questions from these examinations from a long span of over 25 years (1987 onwards) have been solved in the book.

About the Author

Dr. B.N.D. Narasinga Rao has over 25 years of teaching, research and consultancy experience which prompted him to write the present book on Soil Mechanics and Foundation Engineering. The author was the resource person for 37 workshops and conferences since 1989.

Table of Contents:
1 Introduction 1.1 Introduction 1.2 Definitions 1.3 History of Soil Mechanics 1.4 Applications of Soil Mechanics 1.5 Professional Activities in Geotechnical Engineering 2 Origin and Formation of Soils 2.1 Introduction 2.2 Soil Formation 2.3 Weathering 2.4 Erosion 2.5 Factors Influencing Weathering and Soil Formation 2.6 Residual Soils 2.7 Transported Soils 2.8 Types of Soil Profile 2.9 Soil Horizons 2.10 Soil Deposits of India 3 Soil Mineralogy and Structure 3.1 Introduction 3.2 General Types of Soils Based on Particle Size 3.3 Soil Mineralogy 3.4 Primary and Secondary Minerals 3.5 Bonding in Soils 3.6 Mineralogy of Fine-Grained Soils 3.7 Kaolinite 3.8 Montmorillonite 3.9 Illite 3.10 Chlorite 3.11 Vermiculite 3.12 Isomorphous Substitution 3.13 Properties of Clay Minerals 3.14 Identification of Clay Minerals 3.15 Soil Structure and Soil Fabric 3.16 Mineralogy of Cohesionless Soils 4 Physical Properties of Soils 4.1 Introduction 4.2 Three-Phase System of Soil 4.3 Phase Diagram of Soil 4.4 Physical Properties of Soils 4.5 Functional Relationships between Physical Properties 4.6 Physical Properties in Terms of Mass 4.7 Functional Relationships of Physical Properties in Terms of Mass 4.8 Preparation of Soil Samples for Determination of Physical Properties 4.9 Determination of Water Content 4.10 Determination of Specific Gravity 4.11 Determination of in-situ Density 4.12 Relative Density 5 Plasticity Characteristics of Soils 5.1 Introduction 5.2 Consistency 5.3 Consistency Limits 5.4 Liquid Limit 5.5 Plastic Limit 5.6 Index Properties of Soils 5.7 Shrinkage Limit 5.8 Uses of Consistency Limits 5.9 Classification of Soils Based on Index Properties 6 Soil Classification 6.1 Need for Soil Classification 6.2 Particle Size Classification 6.3 Scientific Basis for Soil Classification 6.4 Grain Size Analysis of Soil 6.5 Grain Size Distribution Curve 6.6 Textural Classification 6.7 AASHTO Classification 6.8 Unified Soil Classification System 6.9 Indian Standard Soil Classification (IS:1498 - 1970) 6.10 Field Identification Tests for Fine-Grained Soils 7 Stresses Due to Self-Weight 7.1 Introduction 7.2 Total Stress 7.3 Pore Water Pressure 7.4 Effective Stress Principle 7.5 Effective Stress 8 Vertical Stress Due to Applied Loads 8.1 Introduction 8.2 Boussinesq Theory for Vertical Stress Due to Concentrated Load 8.3 Vertical Stress below Strip Footing 8.4 Newmark’s Influence Chart 8.5 Westergaard’s Theory for Vertical Stress 8.6 The 2:1 Distribution Method 8.7 Comparison of Different Methods for Determination of Vertical Stress 9 Permeability of Soils 9.1 Introduction 9.2 Types of Soil Water 9.3 Flow of Water through Soil 9.4 Permeability 9.5 Darcy’s Law 9.6 Coefficient of Absolute Permeability 9.7 Factors Affecting Permeability of Soils 9.8 Determination of Permeability 9.9 Constant Head Permeability Test 9.10 Falling Head Permeability Test 9.11 Capillary Permeability Test 9.12 Consolidation Test 9.13 Permeability of Stratified Soil Deposits 10 Seepage Analysis 10.1 Introduction 10.2 Types of Soil Formations 10.3 Basic Definitions 10.4 In Situ Tests for Determination of Permeability 10.5 Pumping-Out Tests 10.6 Pumping-In Tests 10.7 Seepage Velocity 10.8 Total Head, Pressure Head, and Datum Head 10.9 Seepage Pressure and Quicksand 10.10 Laplace Equation for Two-Dimensional Flow 10.11 Flow Net 10.12 Methods of Drawing a Flow Net 10.13 Calculation of Hydraulic Parameters from a Flow Net 10.14 Flow Net for Anisotropic Soils 10.15 Phreatic Line in Earth Dams 10.16 Failure of Hydraulic Structures by Piping 10.17 Seepage Control in Hydraulic Structures: Prevention of Piping Failures 10.18 Design of Graded Filter 11 Consolidation 11.1 Introduction 11.2 Significance of Compressibility and Consolidation 11.3 Mechanism of Consolidation: Terzaghi’s Soil-Spring Analogy 11.4 Parameters for Measurement of Compressibility of Soils 11.5 Determination of Consolidation Settlement 11.6 Terzaghi’s Theory of Consolidation 11.7 Odometer or Consolidation Test 11.8 Pre-Compression and Pre-Consolidation Pressure 11.9 Effect of Stress History on Compression of Clays 11.10 Components of Settlement 11.11 Construction Period Correction: Prediction of Field Consolidation Curve 11.12 Acceleration of Consolidation Using Sand Drains 11.13 Three-Dimensional Consolidation 12 Compaction 12.1 Introduction 12.2 Principle of Compaction 12.3 Effect of Compaction on Engineering Properties of the Soil 12.4 Laboratory Compaction Test 12.5 IS Light Compaction Test 12.6 IS Heavy Compaction Test 12.7 Ideal Compaction Curve-Zero Air Void Line 12.8 Compaction Curve for Sands 12.9 Factors Affecting Compaction 12.10 Field Compaction Procedure 13 Shear Strength 13.1 Introduction 13.2 Principal Stresses and Principal Planes 13.3 Mohr’s Circle of Stresses 13.4 Mohr-Coulomb Failure Theory 13.5 Determination of Shear Strength 13.6 Direct Shear Test 13.7 Triaxial Compression Test 13.8 Unconfined Compression Test 13.9 Vane Shear Test 13.10 Bore Hole Shear Test 13.11 Sensitivity 13.12 Pore Pressure Parameters 13.13 Stress Path 14 Soil Exploration 14.1 Introduction 14.2 Need for Soil Exploration 14.3 Planning and Execution of Soil Exploration 14.4 Methods of Soil Exploration 14.5 Soil Samples 14.6 Soil Samplers 14.7 Location of GWT 14.8 In Situ Tests 14.9 Soil Investigation Report 15 Lateral Earth Pressure 15.1 Introduction 15.2 Lateral Earth Pressure 15.3 Types of Lateral Earth Pressure 15.4 Derivation of Expression for Earth Pressure at Rest 15.5 Rankine’s Theory of Active Earth Pressure for Cohesionless Backfill 15.6 Rankine’s Active Earth Pressure for Cohesive Backfill 15.7 Fully Submerged Cohesive Backfill 15.8 Rankine’s Theory of Passive Earth Pressure for Cohesionless Backfill 15.9 Rankine’s Passive Earth Pressure for Cohesive Backfill 15.10 Rankine’s Earth Pressure for Retaining Wall with Inclined Back 15.11 Coulomb’s Wedge Theory for Earth Pressure 15.12 Poncelet (or Rebhan’s) Construction for Active Earth Pressure 15.13 Poncelet (or Rebhan’s) Construction for Passive Earth Pressure 15.14 Culmann’s Construction for Active Earth Pressure 15.15 Coulomb’s Theory of Active Earth Pressure for Cohesive Backfill 15.16 Trial Wedge Method for Lateral Earth Pressure 15.17 Coulomb’s Theory for Passive Earth Pressure for Cohesionless Backfill 15.18 Passive Earth Pressure by Friction Circle Method 16 Retaining Structures 16.1 Introduction 16.2 Selection of Backfill and Drainage 16.3 Types of Retaining Walls 16.4 Cantilever Sheet Pile in Granular Soil 16.5 Cantilever Sheet Pile in Cohesive Soil 16.6 Anchored Sheet Pile in Cohesionless Soil: Free Earth Support Method 16.7 Anchored Sheet Pile in Cohesive Soil 16.8 Anchored Sheet Pile in Granular Soil: Fixed Earth Support Method 16.9 Rowe’s Moment Reduction for Anchored Wall 16.10 Miscellaneous Types of Retaining Structures 17 Stability of Earth Slopes 17.1 Introduction 17.2 Definition of Factor of Safety 17.3 Types of Slope Failures 17.4 Stability Analysis of Infinite Slopes 17.5 Stability Analysis of Finite Slopes: Culmann’s Method 17.6 Stability Analysis of Finite Slopes Using the Swedish Circle Method 17.7 Stability Analysis of Slopes of Earth Dams 17.8 Bishop’s Simplified Method of Slices 17.9 Friction Circle Method 17.10 Taylor’s Stability Number and Stability Charts 17.11 Improving the Stability of Slopes 18 Bearing Capacity of Shallow Foundations 18.1 Introduction 18.2 Design Criteria of Shallow Foundations 18.3 Basic Terms and Definitions 18.4 Rankine’s Theory of Bearing Capacity 18.5 Prandtl’s Theory of Bearing Capacity 18.6 Terzaghi’s Theory of Bearing Capacity 18.7 Types of Shear Failure of Soil 18.8 Skempton’s Theory of Bearing Capacity 18.9 Meyerhof’s Theory 18.10 Hansen’s Theory of Bearing Capacity 18.11 Vesic’s Theory of Bearing Capacity 18.12 IS Code Method 19 Settlement of Shallow Foundations 19.1 Introduction 19.2 Depth of Foundation 19.3 Types of Shallow Foundations 19.4 Components of Settlement 19.5 Steps Involved in Settlement Computation 19.6 Estimation of Settlements for Cohesionless Soils 19.7 Plate Load Test 19.8 Estimation of Settlement for Cohesive Soils 19.9 Correction to Total Settlement for Depth and Rigidity of Foundation 19.10 Differential Settlements and Distortion 19.11 Allowable Settlements 19.12 Indian Standard (IS:1080) Specifications for Foundations 20 Pile Foundations 20.1 Introduction 20.2 Classification of Pile Foundations 20.3 Construction of Piles 20.4 Load-Transfer Mechanism from Pile to Soil 20.5 Estimation of Load Capacity of Piles: Static Formulae 20.6 Estimation of Load Capacity of Piles: Dynamic Formulae 20.7 Estimation of Load Capacity of Pile from SCPT 20.8 Estimation of Load Capacity from SPT 20.9 Estimation of Load Capacity from Load Test on Piles 20.10 Group Action in Piles 20.11 Settlement of a Pile Group 20.12 Negative Skin Friction 20.13 Under-Ream Pile Foundations 21 Well Foundations 21.1 Introduction 21.2 Caissons 21.3 Shapes of Well Foundations 21.4 Components of Well Foundation 21.5 Depth of a Well Foundation 21.6 Forces Acting on Well Foundations 21.7 Stability Analysis of Well Foundations 21.8 Factor of Safety 21.9 Construction of Well Foundations 21.10 Tilting and Shifting of Wells In CD 22 Soil Dynamics and Machine Foundations 22.1 Introduction 22.2 Types of Machines 22.3 Types of Machine Foundations 22.4 Methods of Dynamic Analysis 22.5 Procedure for Dynamic Analysis of Machine Foundation 22.6 Dynamic Soil Properties 22.7 Design Criteria of Machine Foundations 22.8 Vibration and Shock Isolation 23 Ground Improvement Techniques 23.1 Introduction 23.2 Objectives of Ground Improvement 23.3 Classification of Ground Improvement Methods 23.4 Mechanical Stabilization 23.5 Sand Compaction Piles 23.6 Blasting 23.7 Dynamic Compaction 23.8 Preloading 23.9 Sand Drains 23.10 Prefabricated Vertical Drains 23.11 Stone Columns 23.12 Reinforced Earth 23.13 Soil Nailing 23.14 Geosynthetics 23.15 Foundation Grouting 23.16 In-Situ Soil Mixing 23.17 Seepage Control and Dewatering Systems 23.18 Freezing 23.19 Heating 24 Foundations in Expansive Soils 24.1 Introduction 24.2 Damage to Structures Built on Expansive Soils 24.3 Factors Affecting Seasonal Moisture Variations 24.4 Active Zone 24.5 Mechanism of Swelling 24.6 Factors Influencing Heave 24.7 Estimation of Heave 24.8 Determination of Swelling Pressure 24.9 Identification and Classification of Expansive Soils 24.10 Foundation Techniques in Expansive Soils 24.11 Pavements on Expansive Soils 24.12 Remedial Options Summary Objective Questions Review Questions Answers Bibliography List of IS Codes