27371 - Agricultural soil mechanics

Learning outcomes

At the end of the course, students will know all the principles of geotechnical engineering and they will be able to apply such knowledge for the design and protection of land resources.

Course contents

Lectures (36 hours):

Module 1: Soil Classification

Genesis, definitions. Technical properties and physical characteristics of the soil. Identification and classification of soils. Grain size distribution curve. Sedimentation and sieving. Atterberg limits: Liquid limit, plastic limit, shrinkage limit, plasticity index, clay activity index, plasticity chart, determination of liquid limit using the Casagrande spoon and the cone penetrometer method, determination of plastic limit.

Module 2: Soil Elasticity

Mechanical properties and elasticity. Hooke's law. Stress-strain relationship. Young's modulus, Poisson's coefficient, shear modulus. Normal stress and shear stress. Stress state. Shear-strain relationship.

Module 3: Shear Strength

Possible and impossible states, and the limit curve. Deformations in the soil. Shear strength and failure surfaces. Coulomb failure line, soil friction angle, cohesion, Mohr-Coulomb failure criteria. Mohr circles: Principal directions, principal stresses. Failure mechanisms.

Module 4: Soil Strains

Settlement, differential settlement. Consolidation, overconsolidation. Compaction. Determining factors.

Module 5: In-Situ Investigations and Laboratory Tests

Sampling, disturbed and undisturbed. Laboratory tests: moisture content measurement, specific gravity, permeability, shear strength: Triaxial compression test (CD, CU, UU), direct shear test (Casagrande's box). Unconfined compression test. Consolidation test. Proctor test. In-situ investigations.

Module 6: Earth Pressure

Surface loads, weight of the soil. Rankine's theory: passive pressure, active pressure, at-rest pressure. Coulomb's theory: pressures.

Module 7: Foundations

Function and types. Mechanisms of failure for shallow foundations, Terzaghi's theory for calculating the bearing capacity of soil, calculation of the bearing capacity safety factor.

Module 8: Retaining Walls

Gravity walls. Cantilever walls. Double live pile. Sheet piles (Berlin and anchored). Wall stability: definitions. Stability analysis for overturning and sliding. Stability analysis for bearing capacity.

Module 9: Slope Stability

Landslides and slope movements. Predisposing and triggering factors. Classification and types. Stability of infinite slopes for cohesive and non-cohesive soils, stability of finite slopes. Limit Equilibrium Method (LEM). Slice method. Stabilization interventions. Focus on reinforced soils.

Module 10: Hydrogeological Instability

Introduction and definitions. Floods and landslides. Defense and planning. Territorial planning. Risk estimation. Hazard maps. Thematic maps: morphological, geological ones. GIS as tools for prevention. PAI (Hydrogeological Constraint Map) and hazard areas.

Exercises (24 hours):

Stability checks: stable and unstable slopes.Introduction to SSAP software. Exercises using the program for slope stability verification.

Readings/Bibliography

Course material:

• PDF notes provided by the teacher. To aid class learning process, these notes should be printed before each lecture. These notes will be provided with IOL service and they will be accessible to those subscribed to the distribution list.
• Budhu, Muni - Soil mechanics and foundations - John Wiley & Sons, 2008.
  

Discretionary course material:

• J. Facciorusso – Dispense di Geotecnica – Università di Firenze download link: http://people.dicea.unifi.it/johannf/?page=support_geot.
• John Atkinson - Fundamentals of ground engineering - CRC Press.
• Whitlow, Roy- Basic soil mechanics - Longman, 1990.
• Piergiuseppe Froldi - Dissesto idrogeologico e stabilità dei versanti. Consolidamento dei pendii con palificate. Analisi e progettazione - Maggioli Editore, 2015.

The details of the distribution list can be requested by email.The email object has to contain the following string:
"Lista di distribuzione GEOTECNICA AGRARIA".

Teaching methods

Lectures, tutorials, and independent learning will be employed. To take part of the soil mechanics laboratory, it is mandatory to attend preemptively the safety course.

During the course, seminars will be planned and will be held by experts in the field of slope stabilization.

Assessment methods

The course is a module of "Agro-Forestry Hydraulic Systems" together with the course of "Hydraulic Agro-Forestry". Consequently, the final assessment will be the average value of the single assessment of each course.

For this module, the final exam will consist in an oral examination where there are three questions and one will be on the stability analysis of earth ground structures.

The online exam confirmation is mandatory.

Considering that is a module, the recording Teacher is Prof . Francesca Valenti.

Students wishing to take the examination in English are allowed

Teaching tools

Lectures in class, laboratory and computer lab.

Office hours

See the website of Francesca Valenti