72880 - Laboratory of Geotechnical Modelling M

Learning outcomes

The laboratory focuses on the modelling of soil behaviour, specifically in terms of advanced constitutive modelling of soils and numerical modelling of finite problems. Various constitutive models will be examined in detail, providing fundamental principles and the significance of input parameters, enabling students to discern which model to adopt based on soil characteristics and the type of problem to analyse. These skills will then be applied to various geotechnical problems, such as the construction of shallow and deep foundations, embankments, retaining structures, and slope stability. Each case will be studied by adopting the most appropriate constitutive model and using advanced numerical techniques, such as Finite Element Analysis (FEM), to evaluate the response of the soil-geotechnical system. Special emphasis will be placed on analysing the effects of the introduced schematizations and the chosen parameters on the numerical results obtained. Many typical numerical issues that often accompany finite element modelling will also be addressed. Upon acquiring the course credits, students will possess the tools to independently and consciously develop a numerical model of a geotechnical application case, learn to critically analyse the numerical results obtained, and understand the implications on design choices. Acquiring these specific skills will be of great relevance to students' professional training in geotechnical design, which today more than ever requires advanced know-how in numerical modelling.

Course contents

Recommended Prerequisites

Students accessing this course should be familiar with the concepts of Soil Mechanics and be able to analyse the behaviour of major geotechnical structures. These skills are typically acquired in the Geotechnical Structures M mandatory course, within the master's degree program in Civil Engineering. All lessons will be in Italian, so comprehension of the Italian language is necessary to successfully follow the course and use the teaching resources provided by the lecturer.

Program

• The first part of the course deals with the constitutive relationships of soils. Mathematical modelling of experimental behaviour is presented, starting from the theory of perfect plasticity to hardening elastoplasticity. In particular, the Cam Clay model and some recent elastoplastic formulations, such as the "Hardening Soil Model" and the "Soft Soil Creep Model," frequently applied in engineering practice, will be illustrated.
• The second part of the course focuses on the presentation and use of the finite element calculation code "Plaxis 2D," also through the development of simple applied geotechnical problems during lessons.
• The third part of the course, which partially overlaps with the second part, involves the independent development by the student of a finite element numerical model for the analysis of a geotechnical structure (e.g., embankments, shallow foundations, deep foundations, retaining walls). This requires identifying the simplified scheme of the problem to be adopted, selecting the most suitable constitutive model, initial and boundary conditions, and the calculation phases according to the design stages. Depending on the case study considered, the development of the numerical model aims to study deformation processes in soil deposits, both in the short and long term, or to analyse the response of the geotechnical structure up to collapse conditions.

Readings/Bibliography

R. Nova. "Fondamenti di meccanica delle terre." McGraw Hill, Italy

Plaxis 2D Manual, http://www.plaxis.nl/plaxis2d/manuals/

Teaching methods

Lectures, computer practical sessions and tutorials.

Regular attendance at practical exercises is essential for developing the numerical model that will be evaluated at the exam.

Assessment methods

The final exam aims to assess the achievement of the following learning objectives:

• Knowledge of the most common elastoplastic models for soils, typically implemented in commercial calculation codes.

• Ability to develop numerical models of typical elastoplastic geotechnical problems.
• Ability to critically interpret results from numerical modelling.

The assessment is based on an oral exam. The student is asked to present and discuss the numerical model developed during the practical sessions on the geotechnical problem assigned at the beginning of the course. Credits are given on a pass-fail grading system.
In order to attend the exam, students are requested to register using the online procedure available at https://almaesami.unibo.it.

Teaching tools

Blackboard, laptop.

Office hours

See the website of Ilaria Bertolini

See the website of Laura Tonni