Geotechnical Engineering

Code:

M.EC005

Acronym:

EG

Keywords
Classification	Keyword
OFICIAL	Geotechnics

Instance: 2024/2025 - 1S

Active?	Yes
Responsible unit:	Department of Civil and Georesources Engineering
Course/CS Responsible:	Master in Civil Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
M.EC	122	Syllabus	1	-	6	52	162

Teaching language

Portuguese and english
Obs.: Português e Inglês

Objectives

RATIONALE:
Continuing from Soil Mechanics, the curricular unit Geotechnical Engineering deals with the concepts, theories and methods used in Civil Engineering for the design of works, structures and structural components whose conception, analysis and construction are significantly conditioned by the  mechanical behaviour of the surrounding soil masses and discusses the methods employed to charcterize this behaviour. This makes Geotechnical Engineering a fundamental discipline in Civil Engineering.

OBJECTIVES:
Introduction to the concepts, theories and methods used in Civil Engineering for the design of works and structures whose stability relies on the mechanical behaviour of soil masses. Introduction to the methods employed for characterizing that behaviour.

Learning outcomes and competences

KNOWLEDGE:
Describe the main field tests for characterizing the mechanical behaviour of soils. Identify for each test the advantages and limitations. Understand the theories and methodos for limit equilibrium analysis of geotechnical works: embankments, slopes, retaining walls, shallow and deep foundations. Contact with analyses of deformation applied to settlement of shallow foundations. Make preliminary contact with earth works, in particular with the compaction of landfill material. Make contact with the  methods of geotechnical design.

UNDERSTANDING:
Interpret the results of field tests in order to obtain estimates of soil mechanical parameters (strength and stiffness). Explain the effect of time in problems of loading or of excavation of clayey soil masses, in association with the more appropriate options for (short and long term) stability analyses. Explain the phenomena involved in the instabilization of natural slopes. Aprehend the typical strategy for stabilization studies of natural slopes. Discuss the interaction problems between a vertical (or sub-vertical) structural face and the backfill according to their relative motion in order to obtain the corresponding limit interaction force values. Relate them with the magnitude of the strains associated with each case.  Identify the phenomena involved in the foundation interaction with the adjacent soil in failure conditions and in service conditions.  Discuss for service conditions the influence of foundation deformability in the load distribution and settlements, both for isostatic and hyperstatic structures. Take contact with the geotechnical design methods using global or partial safety coefficients, in this case in accordance with Eurocode 7. Take contact with the methods for study of large earth works.

ANALYSIS AND APPLICATION:
Select the mechanical characteristics of soils from the results of field tests. Apply the methods of failure analysis of geotechnical works (retaining walls, embankments, slopes, foundations). Use a computer program to analyze the stability of land masses. Apply methods for evaluating settlements of shallow foundations. Design foundations and retaining walls using global or partial safety factors, in this case applying Eurocode 7.

SYNTHESIS:
Formulate strategies for natural slope stabilization study and design approaches taking into account the contribution of Engineering Geology. Formulate strategies for foundation design, in combination with site investigation studies and the analysis of the loading from the structure to be built. 

Working method

Presencial

Pre-requirements (prior knowledge) and co-requirements (common knowledge)

It is essential to have a good background acquired in Soil Mechanics.

Program

Overall stability of soil masses. Limit equilibrium methods. Method of slices. Fellenius and simplified Bishop methods. Application to natural slopes and to embankments on soft clayey soils.
Stablity of embankments on soft clayey soils. Brief revision of the mechanical behaviour of clays under undrained loading. Change in depth of the undrained shear strength in recent clay deposits. Methods for stability improvement: phased construction, lateral berms, foundation strengthening with stone columns, embankment base reinforcement with geosynthetics, use of lightweight aggregates. Acceleration of the consolidation. Vertical drains.

Cuts and trenches in clays. Short term vs. long term stability of loadings on clay soils. 

Stabilty of natural slopes. Infinite slope. Wedge method. Stabilization of natural slopes. The role of observation. 

Bases for the design of geotechnical works. Global and partial safety factors in Geotechnics. Introduction to Eurocode 7 - Geotechnical Design. 

Compaction. Basic concepts, tests and compaction equipment. Introduction to the design and construction of large embankment works.

Shallow foundations. Bearing capacity. Theoretical solution and correction factors. Immediate settlement. Elastic solution and semi-empirical corrections. Schmertmann method. Criteria for estimating the soil deformation modulus. Allowable settlement. Soil-structure interaction. 

Lateral earth pressure. Rankine active and passive states. Strains associated with Rankine states. Active and passive thrust. Caquot-Kérisel tables. Coulomb theory. Mononobe-Okabe theory to estimate active and passive pressures under seismic conditions. Design of gravity retaining walls.

Penetration tests: SPT, CPTu. Vane-shear test. Plate load test. Ménard pressuremeter test.

Compaction. Basic concepts, tests and compaction equipment. Introduction to the design and construction of large embankment works.

DEMONSTRATION OF THE SYLLABUS COHERENCE WITH THE CURRICULAR UNIT'S OBJECTIVES:
All Civil Engineering works (buildings, bridges, roads, railways, tunnels, ports, dams, etc.) have their behaviour, so also the conception, design, construction and use dependent on the mechanical and hydraulic behaviour of the geological formations at the site. The large majority of these constructions is concentrated in the more densely populated areas, ie near the coast, in the banks or at large rivers estuaries, so in geologically recent areas where the Earth's surface is typically covered by weak soils, sometimes with large thickness.

Mandatory literature

Manuel António de Matos Fernandes; Mecânica dos solos. ISBN: 978-989-746-187-3
Manuel António de Matos Fernandes; Analysis and design of geotechnical structures. ISBN: 978-0-367-02663-9

Comments from the literature

The book Analysis and Design of Geotechnical structures may be read using the link: 

https://doi.org/10.1201/9780429398452

Teaching methods and learning activities

Lectures for the presentation of the concepts, principles and theories with reference to works, accidents and natural phenomena conditioned by the behaviour of soil masses. Tutorials for the resolution of numerical applications from the proposed problem sheets. Use of a computer program for slope stability analysis. Lab classes for the observation and/or presentation of lab and field tests and processing of test results. Field trips.

DEMONSTRATION OF THE COHERENCE BETWEEN THE TEACHING METHODOLOGIES AND THE LEARNING OUTCOMES:
Students are encouraged to calculate the physical characteristics from experimental tests. Classify soils according to the unified classification. Calculate the at-rest stress state and the stress state after ground surface loading. Calculate the hydraulic quantities and the soil stress state for 1D and 2D flow, using flow networks. For clay strata loaded under confined conditions, calculate the consolidation settlement, its evolution in time and design systems to accelerate the consolidation. Calculate the strength parameters in effective stresses and total stresses from the results of lab shear tests. For non confined clay loading conditions, to depict total and effective stress paths between the at-rest state of stress, undrained loading and the end of the consolidation process.

Evaluation Type

Distributed evaluation with final exam

Assessment Components

Designation	Weight (%)
Exame	70,00
Teste	30,00
Total:	100,00

Amount of time allocated to each course unit

Designation	Time (hours)
Frequência das aulas	64,00
Total:	64,00

Eligibility for exams

Achieving final classification requires compliance with attendance at the course unit, according to the MEC assessment rules. It is considered that students meet the attendance requirements if, having been regularly enrolled, the number of absences corresponding to 25% of the the theoretical-practical and practical classes.

Calculation formula of final grade

The final grade is based on the results of two tests made during the semester, plus the final exam. The final grade, CF (on a 0 to 20 scale) is obtained as CF = max{CT ; EF} where CT = 0.15 x CAD1 + 0.15 x CAD2 + 0.70 x EF (CAD1 – mark of test 1; CAD2 – mark of test 2; EF – marks of final exam). 

NOTE 1: The tests associated to the marks CAD1 and CAD2 are optional. In case the student misses any of them the corresponding weight is added to that of the final exam.

NOTE 2: All students enrolled in the course are classified according to this method.

NOTE 3: Students who wish to obtain a final grade over 17 must have at least 17,5 in the final exam and apply for an oral exam.

 

Special assessment (TE, DA, ...)

General rules of MEC are applied.

Observations

SPECIAL RULES FOR MOBILITY STUDENTS In exams, tests and assignments students may use one of the following languages: Portuguese, English, Spanish or French.

ESTIMATED STUDY TIME OUT OF CLASS: 3 hours per week.