31428 - Geotechnics T

Course Unit Page

Academic Year 2018/2019

Learning outcomes

The course aims to give students an introduction to the principles of Soil Mechanics. You will learn about the behaviour of soils as engineering materials, in a wide variety of loading conditions. Moreover, you will be introduced to the basic analytical methods for stability analyses of earth structures like slopes, embankments, cuts. The final aim of the course is to provide a solid basic knowledge for solving simple geotechnical problems as well as for later work on geotechnical engineering within the Master programme.

Course contents

Requirements - Prior knowledge

A prior knowledge of the Continuum Mechanics basic concepts, thought within the "Mechanics of Solids and Structures Course", is required to successfully attend this Course.

Lectures and tutorials are given in Italian. Therefore fluent spoken and written Italian is a necessary prerequisite.

COURSE CONTENTS

Index and classification properties of soils. The origin and nature of soils. Soil mineralogy. Soil structure and fabric. Phase relationships. Grain size and grain size distribution. Atterberg limits. Soil classification systems.

Water in soils. Pore water properties. The principle of effective stress. Capillary phenomena in soils. Flow through porous media. Darcy's law and soil permeability. Laboratory measurement of permeability. Seepage forces, quicksand and liquefaction. Two dimensional flow, flownets.

Stresses in soils. Basic continuum mechanics applied to soils. Vertical stress distribution due to self-weight of soils. Lateral earth pressure at rest. Loading history. Preconsolidation stress. Overconsolidated soils. Stress distribution due to surface loads from elastic theory.

Soil compressibility. The oedometer test. Terzaghi's theory of one dimensional consolidation. Determination of compression and consolidation coefficients from oedometer tests. Primary compression settlement calculation. Secondary compression.

Shear strength of soils. The Mohr-Coulomb failure criterion. Shear strength of soils. Laboratory tests to determine shear strength parameters: direct shear apparatus and triaxial test. Shear strength of granular soils. Shear strength of clays. Residual strength. End-of-construction and long-term stability.

Soil investigation. Purposes of a soil investigation. Soil exploration methods. Boreholes and soil sampling. Site investigations: basics of cone penetration testing.

Lateral earth pressure. Plasticity and limit equilibrium methods. Active earth pressure, passive earth pressure, coefficients of earth pressure, active and passive pressure distributions. Unsupported cuts in cohesive soils.

Readings/Bibliography

BERARDI R. Fondamenti di Geotecnica. 3rd Edition, Città Studi Edizioni, 2017.

TONNI L., GOTTARDI G. Esercizi di Geotecnica. Collana Progetto Leonardo, Società Editrice Esculapio, 2010.

Teaching methods

Teaching methods include theoretical lectures interspersed with tutorial exercises in which theory is applied to solve common geotechnical problems.

A visit to the Geotechnical Laboratory of the DICAM Department will be also part of the activities. The students, divided into small groups, will be able to see the main geotechnical apparatuses for soil characterization and learn about the procedures to carry out the tests.

Assessment methods

The examination at the end of the course aims at assessing the achievement of the following objectives:

  • good understanding of the mechanical behaviour of soils under static loading conditions;
  • awareness of the application of soil mechanics principles to geotechnical engineering problems.

The assessment is based on a mandatory written exam in conjunction with an optional oral exam. The written exam, lasting 90 minutes, consists of two questions (theoretical topics covered in the course and exercises). The evaluation of the writtem exam will take into account the relevance, technical correctness and completeness of the answers with respect to the proposed questions, as well as clarity in presentation and knowledge of the technical glossary. Examples of the questions included in the written tests in the last years can be downloaded from the online platform https://iol.unibo.it/. Access is limited to students of the Bologna University. Details about the procedure for downloading files are provided at the beginning of the course.

After passing the written exam (minimum score 18/30), students are free to decide whether to take the oral exam or register the written examination result. Decision must be taken by the date of the first available oral exam.

Before sitting for both the written and oral exams, students must register using the online procedure available at https://almaesami.unibo.it.

Teaching tools

Laptop, slide projector and blackbord.

Powerpoint presentations of lectures can be downloaded in pdf format from the online platform https://iol.unibo.it. Access is limited to students of the Bologna University. Details about the procedure for downloading files are provided at the beginning of the course.

Office hours

See the website of Laura Tonni