31596 - Principles of Geotechnics T

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Quality education Life on land

Academic Year 2021/2022

Learning outcomes

The course aims at providing students with principles and fundamental concepts of Soil Mechanics. The students will learn about the behaviour of soil as engineering material and the main experimental methodologies for the determination of their physical and mechanical parameters. The final goal is to provide a sound basic knowledge for solving simple geotechnical problems as well as for continuing further education on Geotechnical Engineering.

Course contents

Index soil properties and classification systems. Origin of natural soils. Soil mineralogy. Soil structure and fabric. Phase relationships. Grain size distribution. Atterberg limits. Nature and state properties. Soil classification systems.

Initial state and stress history. Basic continuum mechanics applied to soils. Stress state representation and sign convention. Effective stress principle. Vertical stress profile due to self-weight. Stress state history. Preconsolidation stress and overconsolidated soils. Lateral earth pressure at rest.

Water in soils. Pore water properties. Confined and unconfined acquifers. Capillarity, shrinkage and swelling phenomena in soils. Water flow through porous media: Darcy's law and soil permeability. Seepage forces and critical hydraulic gradient. Two dimensional steady flow and flownets.

Soil compressibility and consolidation rate. The oedometer test. Compressibility parameters and primary compression settlement calculation. Terzaghi's theory of one dimensional consolidation. Secondary compression.

Mechanical behaviour of soils. General aspects on mechanical response of soils. Stress induced distribution from elastic theory. The Mohr-Coulomb failure criterion. Shear strength and critical state. Analysis in terms of effective and total stresses. Shear strength parameters and their experimental determination: direct shear and triaxial laboratory tests. Shear strength and deformability of coarse-grained and fine-grained soils. Residual shear strength. Short-term and long-term stability analyses.

Soil investigation and monitoring. Geotechnical design and regulations. The geotechnical model of the subsoil. Purposes of soil investigations. Soil exploration methods. Boreholes and soil sampling. In-situ testing: standard penetration test, cone penetration test, piezocone test. Geotechnical site monitoring: piezometers and inclinometers.

Lateral earth pressure. Plasticity and limit equilibrium methods. Earth pressure coefficients, active and passive earth pressure distributions. Critical height of vertical unsupported cuts in cohesive soils.

Readings/Bibliography

Lecture notes.

Riccardo BERARDI: Fondamenti di Geotecnica. Città Studi Edizioni, Fourth Edition, 2021.

Laura TONNI e Guido GOTTARDI: Esercizi di Geotecnica. Esculapio Bologna, 2010.

Teaching methods

They include both lectures and tutorial exercises, in which theory is applied to solve simple common geotechnical problems. A visit to the Soil Mechanics Laboratory is typically arranged, also online.

Assessment methods

Assessment includes both written and oral exams. They are integrated and indivisible parts of each single exam date. The overall assessment takes into account both parts.

Office hours

See the website of Guido Gottardi