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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

Module leaders are revising this content in light of the Covid 19 restrictions.
Revised and approved detail information will be available by 17 August.

Assessment Methods

Module leaders are revising this content in light of the Covid 19 restrictions.
Revised and approved detail information will be available by 17 August.

Reading Lists

Timetable