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Module

CEG8214 : Soil Modelling and Numerical Methods

  • Offered for Year: 2020/21
  • Module Leader(s): Dr Mohamed Rouainia
  • Lecturer: Dr Sadegh Nadimi
  • Owning School: Engineering
  • Teaching Location: Newcastle City Campus
Semesters
Semester 2 Credit Value: 20
ECTS Credits: 10.0

Aims

The aims of this module are:

1. To introduce a range of constitutive models capable of describing soil behaviour.
2. To provide students with an understanding of the concepts and principles underlying partially unsaturated soil behaviour.
3. To provide an understanding of the principles of numerical modelling.
4. To enable students to develop a working knowledge of a geotechnical finite element program.
5.To introduce students to the discrete element method and its application to geomechanics
6. To introduce students to the benefits of automating numerical analysis through scripting.

Module Summary:

This module will deliver an introduction to the basic features of commonly used constitutive models capable of describing saturated and unsaturated soil behaviour and will provide an understanding of the principles of numerical modelling. It will introduce the advantages and limitations of different models of soil behaviour, and strategies to select the appropriate soil parameters. Presentations and specially prepared notes and tutorial exercises are combined with the use of geotechnical finite element and discrete element software to provide the students with a thorough knowledge and understanding of soil modelling. The use of automation to make finite element analysis an even more powerful design tool will be introduced using a Python-based remote scripting interface.

Outline Of Syllabus

1. Introduction – design objectives, theoretical considerations, physical and analytical models.
2. Elastic models – characteristics of soil behaviour, strain increments and stress variables, elasticity, drained triaxial test, undrained triaxial test, measurement of elastic parameters, oedometer, in-situ geophysics, plate loading, pressuremeter, anisotropy, nonlinearity-secant and tangent stiffness, advantages and limitations of elastic models.
3. Elastic-plastic models – yield surface-Tresca criterion, Von-Mises criterion, Mohr-Coulomb criterion, hardening models, plastic flow rules.
4. Elastic-perfectly plastic Mohr-Coulomb model – Elastic properties, yield criterion, flow rule, elastic-plastic stiffness matrix, selection of soil parameters.
5. Extended Mohr-Coulomb model
6. Cam-clay model –3D space, Isotropic consolidation, critical state line, model ingredients, drained test on NC clay, undrained test on NC clay, elastic properties, yield surface, flow rule, hardening rule, compliance matrix.
7. Stress paths – foundation loading, slope stability, stress path, 2D stress space, 3D stress space, examples of stress paths, pore pressure changes, application of stress paths.
8. Partially saturated soil models – effective stress in partially saturated soil, effect of suction volumetric change, effect of suction on strength behaviour, water retention curves, constitutive modelling
9. Finite element method – Introduction; how does the FE work, mathematical foundations, nodes, elements and shape functions, principle of virtual displacement, external work, internal work.
10. DEM – Introduction, theoretical background, contact mechanics, applications (angle of repose, cone penetration test, tunnelling, etc.), data analysis.
11. Automation – command line in Plaxis 2D, Python remote scripting interface, basic programming in Python, automation of input (model building and construction sequencing), and automation of output (results post-processing).

Teaching Methods

Please note that module leaders are reviewing the module teaching and assessment methods for Semester 2 modules, in light of the Covid-19 restrictions. There may also be a few further changes to Semester 1 modules. Final information will be available by the end of August 2020 in for Semester 1 modules and the end of October 2020 for Semester 2 modules.

Teaching Activities
Category Activity Number Length Student Hours Comment
Scheduled Learning And Teaching ActivitiesLecture20:301:00via Canvas - Module intro/recap. Familiarise with; soil modelling, numerical methods & reading list
Scheduled Learning And Teaching ActivitiesLecture241:0024:00Canvas - lecture materials & published text E.g, short narration to introduce topic plus reading
Guided Independent StudyAssessment preparation and completion360:3018:00Revision for exams
Guided Independent StudyAssessment preparation and completion11:001:00Group Report
Guided Independent StudyAssessment preparation and completion12:002:00Exam
Guided Independent StudyDirected research and reading241:0024:00Studying software manuals and tutorials that accompany taught and computer sessions
Guided Independent StudyDirected research and reading451:0045:00Background reading of course texts
Scheduled Learning And Teaching ActivitiesPractical23:006:00Online Sync - Computer Tutorials
Scheduled Learning And Teaching ActivitiesPractical33:009:00PiP - computer sessions
Guided Independent StudyDirected research and reading451:0045:00Reading Lecture Notes
Guided Independent StudySkills practice120:0020:00N/A
Scheduled Learning And Teaching ActivitiesDrop-in/surgery21:002:00Structured Non-synchronous discussion
Scheduled Learning And Teaching ActivitiesModule talk31:003:00Online Sync - Numerical Exercises
Total200:00
Teaching Rationale And Relationship

The module is taught as an intensive block in order to provide an immersive learning experience with a flexible integration of lecture, tutorial and practical sessions. This format also allows part time and full time students and CPD delegates to attend. Teaching and learning is by a combination of presentations, directed reading and through the use of specially prepared notes to explain the principles of numerical modelling in geotechnical engineering, small group teaching exercises, guided tutorials on geotechnical finite element and discrete element software. The computer practical sessions provide real-world examples of the theory presented in the lectures. It allows opportunities to develop numerical analysis skills and it relates directly to the assessment.

Assessment Methods

Please note that module leaders are reviewing the module teaching and assessment methods for Semester 2 modules, in light of the Covid-19 restrictions. There may also be a few further changes to Semester 1 modules. Final information will be available by the end of August 2020 in for Semester 1 modules and the end of October 2020 for Semester 2 modules.

The format of resits will be determined by the Board of Examiners

Exams
Description Length Semester When Set Percentage Comment
Written Examination1202A70Unseen written examination.
Other Assessment
Description Semester When Set Percentage Comment
Report2M30Group work (approx. 16 pages) - experience of factors that influence results of numerical analysis.
Assessment Rationale And Relationship

A formal take home examination will be used to assess understanding of theoretical aspects of commonly used models of soil behaviour and stress paths. The coursework will develop students' understanding of the constitutive and numerical aspects of geotechnical design of earth structures and enhance their technical skills in undertaking parametric studies to further evaluate modelling outputs.

Reading Lists

Timetable