CT-221                                                                        Soil Mechanics                                                                         4 (3+1)


The main aim of this course is to acquaint students with the branch of science dealing with structure, engineering properties and reactions (behaviour) of soils under loading, weathering and varying environmental conditions i.e. Soil Mechanics. It studies soils theoretically and practically for building of structures using it and over it using knowled.ge of physics, mechanics, and hydraulics applied to study the behaviour. The science deals with the physical properties of soils and the relevance of these properties as they affect soil strength, stability, and drainage. This course is aimed. to establish a sound understanding of mutual interaction of soils and structures with the help of Soil Mechanics as it is the basis for all geotechnical applications, be it integrity of a structure or stability of a road or dam. Starting from origin of soil, the course covers the fundamental multi-phase nature of soils, provides an understanding of soil description and classification, stress related concepts, seepage, settlement and compaction problems.


Course Outline

  • Significance. Soil, rock and their types and formation. Physical properties of soil: water content, voids ratio, porosity, degree of saturation, specific gravity, unit weight and their determination, mass-volume relationships.
  • Soil Classification: Principle properties of soil (natural moisture content, density, specific gravity, void ratio, porosity, degree of saturation). Volumetric and volume weight relationships. Index properties of soil (Grain size distribution, consistency limits). Purpose of soil classification, engineering soil classification systems (ASTM or USCS, AASHTO).
  • Geotechnical Investigation: Scope and objective, exploration methods, field tests (SPT,CPT, Plate load Test, Pressure meter, Dilatometer Test)
  • Permeability and Seepage: Darcy's law, factors affecting permeability, laboratory and field determination of permeability, capillary and its effects.
  • Seepage force. Introduction to flow net, Estimation of seepage quantity. Quick sand condition. Sand boiling Filters.
  • Stresses in Soil: Geostatic stresses, total and effective stresses, stress from surface loads. Lateral stress, Stress influence charts/diagrams and their uses
  • Compaction: Fundamentals, moisture density relationship, compaction standards, factors affecting compaction, field control and measurements of insitu density. Field compaction equipment.
  • Consolidation: Definitions, consolidation, consolidation test and data reduction, naturally consolidated clayey and partially consolidated clayey soils, settlement and rate of settlement. Shear strength of soil, Coulomb‟s law, shear strength parameters (c & fi), cohesive and non- cohesive soils. Laboratory and field evaluation of (c & fi). Utility of shear strength parameters


Primary Books

1.R. Whitlow, “Basic Soil Mechanics”  -Longman Pub Group

2.Prof. Dr. Shaukat Ali Khan, “Soil Mechanics”

3.T. William Lambe Robert V. Whitman”Soil Mechanics” (Wiley Series in Geotechnical Engineering).

Secondary Books

1.Braja M. Das, Khaled Sobhan, “Principles of Geotechnical Engineering”, 8th SI edition-Cengage Learning (2013).

2.Donald P. Coduto, “Geotechnical Engineering” (Principles and practices)

Course Material