Intended as an introductory text in soil mechanics, the seventh edition of Das, PRINCIPLES OF GEOTECHNICAL ENGINEERING offers an overview of soil properties and mechanics together with coverage of field practices and basic engineering procedure.

PRINCIPLES OF GEOTECHNICAL ENGINEERING contains more figures and worked out problems than any other text on the market and provides the background information needed to support study in later design-oriented courses or in professional practice.

**1. GEOTECHNICAL ENGINEERING — A HISTORICAL PERSPECTIVE.**

Geotechnical Engineering Prior to the 18th Century. Pre-Classical Period of Soil Mechanics (1700–1776). Classical Soil Mechanics–Phase I (1776–1856). Classical Soil Mechanics–Phase II (1856–1910). Modern Soil Mechanics. Geotechnical Engineering After 1927, End of an Era.

**2. ORIGIN OF SOIL AND GRAIN SIZE.**

Rock Cycle and the Origin of Soil. Soil–Particle Size. Clay Minerals. Specific Gravity (Gs). Mechanical Analysis of Soil. Particle–Size Distribution Curve. Particle Shape.

**3. WEIGHT-VOLUME RELATIONSHIPS.**

Weight–Volume Relationships. Relationships Among Unit Weight. Void Ratio, Moisture Content, and Specific Gravity. Relationships among Unit Weight, Porosity, and Moisture Content. Various Unit-Weight Relationships. Relative Density. Comments on emax and emin.

**4. PLASTICITY AND STRUCTURE OF SOIL.**

Introduction. Liquid Limit (LL). Plastic Limit (PL). Shrinkage Limit (SL). Liquidity Index and Consistency Index. Activity. Plasticity Chart. Soil Structure.

**5. CLASSIFICATION OF SOIL.**

Textural Classification. Classification by Engineering behavior. AASHTO Classification System. Unified Soil Classification System. Summary and Comparison between the AASHTO and Unified Systems.

**6. SOIL COMPACTION.**

Compaction–General Principles. Standard Proctor Test. Factors Affecting Compaction. Modified Proctor Test. Structure of Compacted Clay Soil. Effect of Compaction on Cohesive Soil Properties. Field Compaction. Specifications for Field Compaction. Determination of Field Unit Weight of Compaction. Compaction of Organic Soil and Waste Materials. Special Compaction Techniques.

**7. PERMEABILITY.**

Bernoulli’s Equation. Darcy’s Law. Hydraulic Conductivity. Laboratory Determination of Hydraulic Conductivity. Relationships for Hydraulic Conductivity–Granular Soil. Relationships for Hydraulic Conductivity–Cohesive Soils. Directional Variation of Permeability. Equivalent Hydraulic Conductivity in Stratified Soil. Permeability Test in the Field by Pumping from Wells. In Situ Hydraulic Conductivity of Compacted Clay Soils.

**8. SEEPAGE.**

Laplace’s Equation of Continuity. Continuity Equation for Solution of Simple Flow Problems. Flow Nets. Seepage Calculation from a Flow Net. Flow Nets in Anisotropic Soils. Mathematical Solution for Seepage. Uplift Pressure Under Hydraulic Structures. Seepage Through an Earth Dam on an Impervious Base. L. Casagrande’s Solution for Seepage through an Earth Dam. Filter Design.

**9. _IN SITU_ STRESSES.**

Stresses in Saturated Soil without Seepage. Stresses in Saturated Soil with Upward Seepage. Stresses in Saturated Soil with Downward Seepage. Seepage Force. Heaving in Soil Due to Flow Around Sheet Piles. Use of Filters to Increase the Factor of Safety Against Heave. Effective Stress in Partially Saturated Soil. Capillary Rise in Soils. Effective Stress in the Zone of Capillary Rise.

**10. STRESSES IN A SOIL MASS.**

Normal and Shear Stresses on a Plane. The Pole Method of Finding Stresses Along a Plane. Stresses Caused by a Point Load. Vertical Stress Caused by a Line Load. Vertical Stress Caused by a Horizontal Line Load. Vertical Stress Caused by a Strip Load (Finite Width and Infinite Length). Vertical Stress Due to Embankment Loading. Vertical Stress Below the Center of a Uniformly Loaded Circular Area. Vertical Stress at Any Point Below a Uniformly Loaded Circular Area. Vertical Stress Caused by a Rectangularly Loaded Area. Stress Isobars. Influence Chart for Vertical Pressure.

**11. COMPRESSIBILITY OF SOIL.**

Contact Pressure and Settlement Profile. Relations for Elastic Settlement Calculation. Fundamentals of Consolidation. One-Dimensional Laboratory Consolidation Test. Void Ratio–Pressure Plots. Normally Consolidated and Overconsolidated Clays. Effect of Disturbance on Void Ratio–Pressure Relationship. Calculation of Settlement from One-Dimensional Primary Consolidation. Compression Index (Cc). Swell Index (Cs). Secondary Consolidation Settlement. Time Rate of Consolidation. Coefficient of Consolidation. Calculation of Consolidation Settlement Under a Foundation. A Case History–Settlement Due to a Preload Fill

for Construction of Tampa VA Hospital. Method of Accelerating Consolidation Settlement. Precompression.

**12. SHEAR STRENGTH OF SOILS.**

Mohr–Coulomb Failure Criterion. Inclination of the Plane of Failure Caused by Shear. Laboratory Tests for Determination of Shear Strength Parameters. Direct Shear Test. Drained Direct Shear Test on Saturated Sand and Clay. General Comments on Direct Shear Test. Triaxial Shear Test–General. Consolidated-Drained Triaxial Test. Consolidated-Undrained Triaxial Test. Unconsolidated-Undrained Triaxial Test. Unconfined Compression Test on Saturated Clay. Empirical Relationships Between Undrained Cohesion and Effective Overburden Pressure. Sensitivity and Thixotropy of Clay. Strength Anisotropy in Clay. Vane Shear Test. Other Methods for Determining Undrained Shear Strength. Shear Strength of Unsaturated Cohesive Soils. Stress Path.

**13. LATERAL EARTH PRESSURE: AT-REST, RANKINE AND COULOMB.**

At-Rest, Active, and Passive Pressures. Earth Pressure At-Rest. Earth Pressure At-Rest for Partially Submerged Soil. Rankine’s Theory of Active Pressure. Theory of Rankine’s Passive Pressure. Yielding of Wall of Limited Height. A Generalized Case for Rankine Active and Passive Pressures–Granular Backfill. Diagrams for Lateral Earth-Pressure Distribution Against Retaining Walls. Rankine’s Pressure for c –f Soil–Inclined Backfill. Coulomb’s Active Pressure. Graphic Solution for Coulomb’s Active Earth Pressure. Coulomb’s Passive Pressure. Active Force on Retaining Walls with Earthquake Forces. Common Types of Retaining Walls in the Field.

**14. LATERAL EARTH PRESSURE:CURVED FAILURE SURFACE.**

Retaining Walls with Friction. Properties of a Logarithmic Spiral. Procedure for Determination of Passive Earth Pressure. (Pp)–Cohesionless Backfill. Coefficient of Passive Earth Pressure (Kp). Passive Force on Walls with Earthquake Forces. Braced Cuts–General. Determination of Active Thrust on Bracing Systems of Open Cuts–Granular Soil. Determination of Active Thrust on Bracing Systems for Cuts–Cohesive Soil.Pressure Variation for Design of Sheetings, Struts, and Wales.

**15. SLOPE STABILITY.**

Introduction–Modes of slope failure. Factor of Safety. Stability of Infinite Slopes. Finite Slopes–General. Analysis of Finite Slopes with Plane Failure Surfaces (Culmann’s Method). Analysis of Finite Slopes with Circular Failure Surfaces–General. Mass Procedure–Slopes in Homogeneous Clay Soil. Mass Procedure–Stability of Saturated Clay Slopes with Earthquake Forces. Mass Procedure–Slopes in Homogeneous Soil. Ordinary Method of Slices. Bishop’s Simplified Method of Slices. Stability Analysis by Method of Slices for Steady-State Seepage. Other Solutions for Steady-State Seepage Condition. A Case History of Slope Failure. Morgenstern’s Method of Slices for Rapid Drawdown Condition. Fluctuation of Factor of Safety of Slopes in Clay Embankment on Saturated Clay.

**16. SOIL-BEARING CAPACITY FOR SHALLOW FOUNDATIONS.**

Ultimate Soil-Bearing Capacity for Shallow Foundations. Terzaghi’s Ultimate Bearing Capacity Equation. Effect of Groundwater Table. Factor of Safety. General Bearing Capacity Equation. A Case History for Evaluation of the Ultimate Bearing Capacity. Ultimate Load for Shallow Foundations Under Eccentric Load. Bearing Capacity of Sand Based on Settlement. Plate-Load Test.

**17.LANDFILL LINERS AND GEOSYNTHETICS.**

Landfill Liners–Overview. Compaction of Clay Soil for Clay Liner Construction. Geosynthetics. Geotextiles. Geomembranes. Geonets. Single Clay Liner and Single Geomembrane Liner Systems. Recent Advances in the Liner Systems for Landfills. Leachate Removal Systems. Closure of Landfills.

**18. SUBSOIL EXPLORATION.**

Planning for Soil Exploration. Boring Methods. Common Sampling Methods. Sample Disturbance. Correlations for Standard Penetration Test. Other In Situ Tests. Rock Coring. Soil Exploration Report.

REVIEW