INGLESE

Basic knowledge of mechanics, geometry and mathematical analysis

Lectures: 48 hours

The design of infrastructures interacting with environment implies a full understanding of the geological characteristics of the construction site to minimize risks for human activities and damage of existing constructions. The ability to anticipate the response of the environment to the construction of excavations, tunnelling, road embankments, dangerous waste disposal plants is particularly needed in geologically complex conditions likewise in the regions of South Europe, where tectonics largely influenced the geology of the environment.

The perspective environmental engineers will be able to apply the methods of structural geology and geomechanics to describe and understand the main geological features of the site to be considered for design. The mapping of discontinuities is the first step in the process of the definition of the ground model, and is totally propaedeutic to the selection of the possible limit states to be considered for judging the suitability of any construction site. Methods of structural geology are presented and their applications in rock mechanics/rock engineering are highlighted in particular through the observation of faults and joints arrest and many case studies where geology features influence the engineering approach to plants design.

Structural geology will be complementary to other courses, specifically environmental geotechnical engineering, slope stability, for its contribution to the understanding of the kinematics of the site and of the controlling micro and macro scale deformation mechanisms. Structural geology allows a better understanding of the origin, the chronology and the mechanical behaviour of discontinuities, and therefore a more accurate rock mass characterization and rock mass classification.

Introduction: Classification of rocks and rock cycle; basic principles of tectonics and stratigraphy.

STRUCTURAL GEOLOGY:

Strain and deformation: definition of strain and deformation; brittle and ductile deformation; homogeneous and heterogeneous strain, dilation, pure and simple shear; longitudinal strain, shear s.; incremental s., finite s., strain in 2D and in 3D, Flinn diagram.
Continuum mechanics (basic principles): stress, normal and shear stress, principal stress axes, types of stress and the importance of stress measurements for engineering design.
Fractures and brittle deformation: nomenclature, systems, tensile fractures, hybrid extension/shear fractures, faults, brittle deformation; mode I, II and III fractures; joints, plumose structure, roughness; aspect ratio, stratabound and non-stratabound fractures, spacing, aperture, length, fracture density; parameters controlling fracture density.
Faults: definition and basic geometric elements; fault terminology, geometry of faults; displacement, slip and separation; fault anatomy;permeability structure of fault zones; conjugate, synthetic and antithetic faults; fault displacement; vertical, horizontal, dip-, strike- and net-slip); fault separation, vertical separation, horizontal separation, dip separation, strike separation, perpendicular (stratigraphic) separation; aseismic creep and seismic deformation, earthquake faulting.
Folds: morphology, classifications; folding mechanisms, buckling, bending, fault-bend folding, fault-propagation folding, detachment folding; multilayer folding; role of viscosity contrast; harmonic, poly-harmonic and disharmonic folding.
Geological maps: types of geological boundaries; lithostratigraphic units; relationships among geological surfaces and topography; geological sections; Plunging folds and their map expression. Fault types and their map expression. Examples of applications for environmental engineering problems (i.e the best choice for waste plants location and related problems due to geological conditions).

GEOMECHANICS:

Geological engineering and Geomechanics: definition and role of the geological engineering, objectives and scopes. Influence of geological factors on geotechnical problems.
Physical and mechanical properties of rocks: rock and soil; rock masses; physical and mechanical characteristics of rocks: physical properties of intact rock; rock classification for geotechnical purposes.
Weathering of rocks: weathering processes, weathering of intact rock and weathering of rock masses.
Groundwater: influence on rock mass behavior, groundwater and the effect of water in the properties of rock masses.
Discontinuities: types of discontinuities, characteristics of discontinuities, shear strength of discontinuity planes, Jv;
Rock mass classification systems: RMR, GSI, RQD.
Barton and Choubey criterion: JCS and JRC; rock mass strength: Hoek and Brown criterion, Mohr Coulomb criterion.
Attitude of planar and linear elements and their representation on stereographic projections: strike, dip direction, angle of dip of planar features; trend and plunge of linear features; use of lower hemisphere, equal-area and equal-angle projections. Basic principles of kinematic analysis.
Engineering geological maps: definition; types of maps; mapping method and data collection; applications.

Exercises:
Exercises on geological maps: geological sketch, relationships among geological surfaces and topography, reading and interpretation of existing geological maps and sections.
Representation of planar and linear elements’ attitude on stereographic projections, fold and fault parameters. Kinematic analysis.

The level of knowledge and understanding of the students will be assessed by the evaluation of a series of practical exercises that will be assigned weekly during the course, as well as by a final oral exam. The exercises will focus on geological maps (relationships among geological surfaces and topography; strike line construction; geological sections), the representation of planar and linear elements’ attitude on stereographic projections, fold and fault parameters as well as bibliographic review for pratical cases.

In order pass the exam successfully, the student should demonstrate a good comprehension of the fundamental principles of the discipline, as well as a problem-solving ability (testified by the exercises mentioned above).

The final mark will be given in /30, possibly cum laude (for outstanding results).

The final evaluation will take into account of the knowledge acquired in all the topics of the course and of the results of the exercises. Maximum marks will be given to students demonstrating a deep understanding of the topics of the course, using an appropriate, competent technical vocabulary in the oral exam.

• Fossen, H. (2016). Structural geology. Cambridge University Press.
• De Vallejo, L. G., & Ferrer, M. (2011). Geological engineering. CRC Press.
• Lisle R. J., Brabham P., Barnes J. W. (2011). Basic Geological Mapping, 5th Edition. Wiley, New York.


Lecture slides available online at: https://learn.univpm.it

Exercises available online at: https://learn.univpm.it