Department of Civil Engineering

Geomechanics - CE204

Credits : 3

Prerequisites : CE201

Compulsory/Optional : Compulsory

To impart knowledge and an understanding of soil mechanics and basic geology, and to familiarize with geotechnical and geological terminology and concepts commonly encountered in engineering practice.
Intended Learning Outcomes
On successful completion of the course, the students should be able to;

  1. Measure basic engineering and physical properties of soils and classify soils for engineering purposes improving the soil properties by compaction where required.
  2. Determine total and effective stress distribution of soils and estimate seepage forces and the seepage through soils using permeability and Darcy's law.
  3. Determine consolidation and shear strength parameters of soils and compute time dependent settlement using one dimensional Terzaghi theory.
  4. Describe internal (plate tectonics theory) and external geological processes (weathering, erosion) and the geology of Sri Lanka.
  5. Identify the rock forming minerals, rock types and classify rocks for engineering purposes.
Course content/Course description
  1. Basic characteristics of soils: Soil formation, structure and phase relationship, mineralogy, soil classification and description, problematic soils
  2. Elements of stress analysis: Effective stress concept, stresses in ground, unsaturated zone, stress-strain relationships, stress state at a point in soil mass, stress induced by applied loads on soils
  3. Permeability and seepage: Darcy’s law, coefficient of permeability, layered soil, anisotropy, seepage theory, flow nets, uplift pressures and seepage forces
  4. Compressibility: Compaction, 1D compression characteristics, oedometer tests, consolidation settlement, Terzaghi 1D consolidation theory, determination of coefficient of consolidation
  5. Shear strength: Mohr-Coulomb failure criterion, shear strength of sand and clays residual strength, pore pressure coefficients, determination of shear strength parameters: triaxial tests (UU, CU, CD), direct shear test, vane shear test
  6. Basic geology: Theory of plate tectonics, rock forming minerals and rock types, geological structures, geological processes, geology of Sri Lanka
Recommended Texts
  1. Craig, RF 2004, Soil Mechanics, Chapman & Hall, 7th edn, New York.
  2. Das, BM 2011, Principles of Foundation Engineering, 7th edn, PWS Publishers.
  3. Lamb, TW & Whitman, RV 2008, Soil Mechanics, SI Version, Wiley India Pvt. Limited.
  4. Cooray, PG 1967 & 1984, An Introduction to the Geology of Sri Lanka, National Museums of Sri Lanka.
  5. Blyth FGH & De Freitas MH, 1984. Geology for Engineers, 7th edn, ELBS Publication.
Time Allocation Hours
Lectures 41
Tutorials 4
Practical -
Assignments -
Assessment Percentage Marks
Assignments/Course work/Quizzes 20
Mid Semester Examination 20
End-semester 60

Department of Civil Engineering