Last Updated S012019


Unit Name Soil Mechanics
Unit Code BCS207S
Unit Duration 1 Semester

Bachelor of Science (Engineering)

Duration 3 years    

Year Level Two
Unit Creator / Reviewer N/A
Core/Elective: Core
Pre/Co-requisites BCS106S, BSC107C
Credit Points


Total Course Credit Points 81 (27 x 3)

Mode of Delivery Online or on-campus. 
Unit Workload (Total student workload including “contact hours” = 10 hours per week; 5 hours per week for 24 week delivery)
Pre-recordings / Lecture – 1.5 hours
Tutorial – 1.5 hours
Guided labs / Group work / Assessments – 2 hours
Personal Study recommended – 5 hours

Unit Description and General Aims

The objective in presenting this unit is to impart to students the principles of soil mechanics, particularly the behaviour of soil under mechanical pressure (stress) and deformation upon interaction with water.

The subject matter covered in this unit will include: the description of soils on the REV scale and the characterisation and classification of soils; the principles of fluid mechanics based on the description of water head using Bernoulli’s and other equations; the determination of flow nets and hydraulic conductivity; fundamental mechanical concepts such as the effective stress concept, strength of soils, consolidation, settlement, and testing procedures. Limited working knowledge of the geological principles and procedures used in a site investigation is introduced, as it is required by engineers involved in foundation works.

At the conclusion of this unit, students will have acquired specialised knowledge of soil mechanics and be able to undertake a variety of soil mechanics analyses.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

  1. Demonstrate a broad knowledge of fundamental phase relationships for soils; understand and apply soil and engineering use classification systems and perform and analyse results in tests for determining the compaction and field density of soils.
    Bloom’s Level 3
  2. Determine and classify the hydraulic conductivity of soils in the lab and in the field.
    Bloom’s Level 3
  3. Analyse seepage flows through saturated soils.
    Bloom’s Level 4
  4. Demonstrate and assess the role of effective stress in soil mechanics theory, and describe the strength of soils based on test results and basic theories.
    Bloom’s Level 4
  5. Describe and analyse consolidation of fine-grained soils and the testing methods that are used for these.
    Bloom’s Level 4
  6. Conduct soil mechanics practicals.
    Bloom’s Level 3

Student assessment

Assessment Type When assessed Weighting (% of total unit marks) Learning Outcomes Assessed

Assessment 1

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation

Example Topic: Foundations of Soil Engineering & Soil Analysis

Students may complete a quiz with MCQ type answers and solve some simple equations to demonstrate a good understanding of the fundamental concepts.

Due after Topic 3 15% 1, 2, 3

Assessment 2 

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation

Example Topic: Classification and Compaction; Soil Water

Students may be asked to provide solutions to simple problems on various topics.

Due after Topic 6 20% 2, 3, 4, 5

Assessment 3

Type: Multi-choice test / Group work / Short answer questions / Practical / Remote Lab / Simulation / Project / Report

Example Topics: Soil Stress and Settlement; Soil Shear Strength OR
Practical - Soil Consistency: The Atterberg Limits; Unified Soil Classification System – Lab and Field Methods; Soil Compaction: The Proctor Test; Soil Classification: The Unified Soil Classification System; Lab Testing Standards for Classification; Triaxial Test Demonstration; and, Shear Box (Direct Shear) Test.

Students may complete a quiz with MCQ type answers or solve some simple problems or use software to complete a practical.

Due after Topic 10 20% 4, 5, 6

Assessment 4

Type: Examination
All topics

An examination with a mix of detailed report type questions and/or simple numerical problems to be completed in 3 hours.

Final Week 40% 1 to 6

Attendance / Tutorial Participation

Example: Presentation, discussion, group work, exercises, self-assessment/reflection, case study analysis, application.

Continuous 5% 1 to 6

Prescribed and Recommended Readings

Required textbook(s)

Knappett, J.A., 2012, Craig's Soil Mechanics, 8th Edition, Spoon Press.

Reference Materials

Das, B.M. 2010, Principles of Geotechnical Engineering, SI version, 8th Edition, Cengage Learning, Stamford, Conn.
Budhu, M., 2011. Soil Mechanics and Foundations, 3rd Edition, John Wiley & Sons, Inc., USA

Unit Content

Topic 1

Introduction – Basic characteristics of soils

• The origin of soils
• The nature of soils
• Plasticity of fine-grained soils
• Particle size analysis
• Soil description and classification
• Phase relationships
• Soil compaction

Topic 2

Seepage – Soil Water and Permeability

• Soil water
• Permeability and testing
• Seepage theory
• Flow Nets
• Anisotropic soil conditions
• Non-homogeneous soil conditions
• Numerical solution using the Finite Difference Method
• Transfer condition
• Seepage through embankment dams
• Filter design

Topics 3 & 4

Effective Stress and Consolidation

• The principle of effective stress
• Numerical solution using the Finite Difference Method
• Response of effective stress to a change in total stress
• Effective stress in partially saturated soils
• Influence of seepage on effective stress
• Liquefaction
• The oedometer test
• Consolidation settlement
• Degree of consolidation
• Terzaghi’s theory of one-dimensional consolidation
• Determination of coefficient of consolidation
• Secondary compression
• Numerical solution using the Finite Difference Method
• Correction for the construction period
• Vertical Drains
• Pre-loading

Topic 5

Soil behaviour in shear

• An introduction to continuum mechanics
• Simple models of soil elasticity
• Simple models of soil plasticity
• Laboratory shear tests
• Shear strength of coarse-grained soils
• Shear strength of saturated fine-grained soils
• The critical state framework
• Residual strength
• Estimating strength parameters from index tests

Topics 6 and 7

Ground Investigation and In-situ Testing

• Methods of intrusive investigation
• Soil Sampling
• Selection of laboratory test method(s)
• Borehole logs
• Cone Penetration Testing (CPT)
• Geophysical methods
• Contaminated ground
• Introduction to In-situ testing
• Standard Penetration Test (SPT)
• Field Vane Test (FVT)
• Pressure-meter Test (PMT)
• Cone Penetration Test (CPT)
• Selection of in-situ test method(s)

Topics 8 and 9

Applications of Soil Mechanics – Shallow and Deep foundations

• Shallow Foundations
• Bearing capacity and limit analysis
• Bearing capacity in undrained materials
• Bearing capacity in drained materials
• Stresses beneath shallow foundations
• Settlements from elastic theory
• Settlements from consolidation theory
• Settlement from in-situ test data 311
• Limit state design
• Deep Foundations
• Pile resistance under compressive loads
• Pile resistance from in-situ test data
• Settlement of piles
• Piles under tensile loads
• Load testing
• Pile groups
• Negative skin friction

Topic 10

Stability of earth-retaining structures

• Basic Concepts of Lateral Earth Pressures
• Coulomb’s Earth Pressure Theory
• Rankine’s Lateral Earth Pressure for a Sloping Backfill and a Sloping Wall Face
• Lateral Earth Pressures for a Total Stress Analysis
• Application of Lateral Earth Pressures to Retaining Walls
• Types of Retaining Walls and Modes of Failure
• Stability of Rigid Retaining Walls
• Stability of Flexible Retaining Walls
• Analysis of Sheet Pile Walls in Uniform Soils
• Analysis of Sheet Pile Walls in Mixed Soils
• Analysis of Cantilever Sheet Pile Walls
• Analysis of Anchored Sheet Pile Walls

Topic 11

Slope stability

• Types of Slope Failure
• Causes of Slope Failure
• Erosion
• Rainfall
• Earthquakes
• Geological Features
• External Loading
• Construction Activities
• Excavated Slopes
• Fill Slopes
• Rapid Drawdown
• Infinite Slopes
• Two-Dimensional Slope Stability Analyses
• Rotational Slope Failures
• Method of Slices (Bishop’s Method, Janbu’s Method)
• Cemented Soils
• Application of the Method of Slices
• Procedure for the Method of Slices
• Stability of Slopes with Simple Geometry (Taylor’s Method, Bishop–Morgenstern Method)
• Factor of Safety


Topic 12

Unit Review

In the final week, students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of students’ work and to clarify any outstanding issues.

Software/Hardware Used


  • Software: N/A

  • Version: N/A

  • Instructions:  N/A

  • Additional resources or files: N/A


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