Course syllabus

Course-PM

ACE150 Soil modelling and numerical analyses lp2 HT20 (7.5 hp)

Course is offered by the department of Architecture and Civil Engineering

Contact details

Examiner and main teacher: minna.karstunen@chalmers.se

Tutorial responsible: Sinem Bozkurt bozkurt@chalmers.se

Course purpose

Short description of the course purpose and content: can be copied from syllabus in Studieportalen. Additional information can be added.

Schedule

Download the schedule.

Course literature

The copies of the lecture notes, made available in the course home page, form a major compendium that the students will be expected to add on via self-study. For additional background reading, reference and self-study, the following books are recommended:
- Lees, A, Geotechnical Finite Element Analysis, ICE Publishing, 2016
- Muir Wood, D. Geotechnical Modelling. Spon Press, 2004 (available in e-book)
- Potts, D. & Zdravkovic L. Finite element analysis in geotechnical engineering- Theory. Thomas Telford,1999.
- Potts, D. & Zdravkovic L. Finite element analysis in geotechnical engineering- Application. Thomas Telford,1999.
- Potts, D., Axelsson K., Grande, L. Schweiger, H. & Long, M. Guidelines for the use of advanced numerical analysis. Thomas Telford, 2002.
- Azizi, F. Applied analysis in geotechnics. E & F. Spon, 2000.
- Muir Wood, D. Soil behaviour and critical state soil mechanics. Cambridge University Press,1990.

Organisation

The techniques and methods are firstly taught via lectures, which contain materials and experience that is not available in any textbooks, supported by self-studies. The theories are applied in numerical modelling via supervised course-specific computer tutorials using Plaxis 2D FE code, which have been designed to develop the competencies step-by-step. The final step from theory to real problems is done as part of coursework exercises:
- Early on during the course each student is asked to identify, study, understand and replicate/discuss results of a geotechnical numerical study published in a peer reviewed scientific article (individual assignment). The results are presented in a form of a summary report.
- As a group of 2-3 people, students are asked to perform numerical studies of real geotechnical problems (starting from real soil data) at boundary value level. The analyses use geotechnical finite element code Plaxis 2D by applying the best practice taught in the course. The results are presented both orally, and in the form of reports.

Changes made since the last occasion

Coursework marks changed based on student feedback: CW1 (individual) 60% and CW2 (group max 3 people) 40%.

Learning outcomes and syllabus

- apply 2D geotechnical finite element (FE) analyses to geotechnical problems 
- understand the role of the constitutive model and numerical analyses in geotechnical design, and how some special features (such as stress initialization, initial state, coupled flow-deformation analyses, non-linear soil models and structural elements) are needed for performing geotechnical finite element analyses;
- distinguish between different constitutive (soil) models, considering both simple and advanced soil models, and thus be able to select an appropriate model for a given geotechnical analysis;
- evaluate appropriate input values for the model parameters of the constitutive models considered, and well as to appreciate the sensitivity of the simulation results to the selected parameter values;
- simplify geotechnical and soil-structure interaction problems to create numerical models with increasing complexity 
- perform coupled 2D analyses of typical geotechnical problems (embankments, slopes, foundations, excavations) with geotechnical finite element analyses, considering both Ultimate Limit State (ULS) and Serviceability Limit State (SLS);
- present, study and critically assess the results of geotechnical numerical analyses;

Content

● Introduction
○ Introduction to numerical analyses in geotechnics
○ Geotechnical vs. structural FE analyses
○ Displacement based FE formulation (incl. some discussion of element types and shape functions, as typical for geotechnical FEA)
○ Role of constitutive model in geotechnical FEA
● Simple constitutive models
○ Elastic models (linear elasticity, non-linear elasticity and elastic anisotropy)
○ Principles of elasto-plastic models
○ Mohr Coulomb model and its limitations
○ Other elastic-perfectly plastic models (von Mises, Tresca, Drucker-Prager)
● Special features of geotechnical FE analyses
○ Creation of in situ stresses and pore pressures
○ Drained and undrained analyses (total stress models vs. effective stress models)
○ Controlling non-linear analyses
○ Coupled consolidation analyses
○ Factor of safety with geotechnical FEA
○ Modelling structural elements in geotechnical FEA (walls, foundations, anchors, geotextiles, drains, piles, interface elements etc.)
● Advanced constitutive models
○ Critical state models (MCC, Soft Soil) and Hardening Soil model (HS)
○ Constitutive models for structured soils (NGI-ADP, S-CLAY1S)
○ Rate-dependent constitutive models (Soft Soil Creep, Creep-SCLAY1S)
○ Small strain stiffness models (HSsmall)
○ Selection of the soil model dependent on the problem and materials involved
○ Parameter sensitivity and optimisation

Link to the syllabus on Studieportalen.

Study plan

Examination including compulsory elements

In order to pass the course, the students need to complete the computer tutorials and to submit satisfactorily the coursework assignments, consisting of individual and group assignments. The final mark is based on the assignment marks (with 40% of the mark is based on group project and 60% based on individual assignment/oral presentation).