72
Geotechnics
REGGIO DI CALABRIA
Overview
Date/time interval
Syllabus
Course Objectives
The course aims to provide the student with the basic knowledge of geotechnics. In particular, the following knowledge will be acquired. Knowledge of the principle of effective stresses. Knowledge of groundwater filtration in steady-state and transient regimes. Knowledge of shear strength and deformability of soils. Knowledge of Earth pressure and earth retaining structures. Knowledge of settlements and bearing capacity of surface foundations.
Upon completion of the course, students will be able to interpret the results of laboratory tests, define a geotechnical subsurface model, and solve simple geotechnical engineering problems such as calculating the settlement and bearing capacity of shallow foundations and design of earth retaining walls.
Attainment of the above skills will be pursued through lectures, consultation of textbooks and/or specific scientific publications, performance of laboratory and design exercises, and individual study of topics covered in the course.
The student will be able to investigate the topics studied with a high degree of autonomy for professional and research purposes.
Course Prerequisites
None
Teaching Methods
lectures, laboratory and design exercises, individual study of topics covered during the course.
Assessment Methods
The exam consists of an oral test aimed to assess the knowledge acquired by the student on the topics covered by the course, independent judgment, learning ability and communication skills. The outcome of the exam will result from an average of the marks assigned on each question posed to the student.
Grading criteria will be the following:
30 cum laude: complete, in-depth and critical knowledge of the topics, excellent language skills, complete and original interpretative ability, full ability to independently apply the knowledge to solve the proposed problems;
28 - 30: complete and in-depth knowledge of the topics, excellent language properties, complete and effective interpretative skills, able to independently apply the knowledge to solve the proposed problems.
24 - 27: knowledge of the topics with a good degree of command, good language skills, correct and safe interpretative skills, good ability to correctly apply most of the knowledge to solve the proposed problems;
20 - 23: adequate knowledge of the topics but limited mastery of them, satisfactory language skills, correct interpretative ability, more than sufficient ability to independently apply the knowledge to solve the proposed problems;
18 - 19: basic knowledge of the main topics, basic knowledge of technical language, sufficient interpretative ability, sufficient ability to apply the basic knowledge acquired;
Insufficient: does not have an acceptable knowledge of the topics covered during the course.
Texts
Notes from lessons and tutorials.
Riccardo Berardi. Fondamenti di Geotecnica. Città Studi Edizioni
Contents
Teaching program
Soil Identification and classification (0.5 cfu). Genes and Structure of clayey and granular soils. Phase relationships. Classification tests: granulometry, aerometry and Atterberg limits. Classification systems: Mit, Uscs, CNR-UNI 10006.
Principle of effective efforts and state variables (0.5 cfu). Presence of water, interstitial pressures. Total and effective stresses, principle of effective stress. Geostatic tensions. History of the tensional state: normal and overcon -solitated land soils. Horizontal trust coefficient at rest, aging. Capillarity phenomena. Representation of tension states, circles of Mohr, stresses paths.
Ground modeling as continuous (0.5 cfu). The elastic model. Young modules in drained and undrained conditions, shear modules, Poisson coefficients, volumetric deformability modules. Application of the theory of elasticity to the calculation of tensions induced by the surface loads, the Boussinesq solution, extension to generic load areas. Notes on elasty-plastic models.
Water in the ground: permeability and filtration in the stationary regime (1 CFU). Permeability coefficient, Darcy's law. Conditions of balance in the presence of filtration. Critical hydraulic gradient. The phenomenon of liquidization. Experimental determination of permeability: theoretical models, laboratory and in situ tests. Equivalent permeability of stratified soils. General equation of filtration. Hydraulic stability of the excavations. Motes of filtration in the stationary regime. Flow nets. Hydrodynamic pressures, filtration flow rates.
Motes of filtration in transitional regime (1 CFU). Monodimensional consolidation theory of Terzaghi (1925). EDOMETRIC TESTS: Determination of pre-consolidation pressure. Determination of the deformability parameters in monodimensional conditions, determination of the primary and secondary consolidation coefficients, influence of the samples. Calculation of settlements in edometric conditions.
Shear resistance of soils and determination of the shear resistance parameters by laboratory tests (1.5 CFU). Failure criteria in drained and undrained conditions. Mohr-Coulomb and Tresca failure criteria. Shear strength parameters : peak, critical state and residual resistance. The influence of physical parameters on the shear strength characteristics. Dependence on the tension state and on the history of the tension state. Direct shear tests., Drained and undrained triaxial tests. Rowe's theory of dilatancy (1962). The concept of critical state. The curved failure envelope: the approaches of Baligh (1975) and Bolton (1984). Effects of the stresse paths, tension history, and of deformation conditions. Traxual tests with different types of consolidation and different stress paths under drained and undrained. Choice of shear strength parameters in stability analysis.
Soil deformability (0.5 cfu). Non-linearity of the stress-strain curves, the hyperbolic model. Determination of deformation modules from triaxial tests. Influence of the physical parameters of the soil, the tension state and the history of the tension state.
Earth pressure and earth retaining structures (1 CFU). Active and passive states. Active and passive earth preassure coefficients in drained and undrained conditions. Retaining walls. Calculation of the earth pressure on the walls in short and long term conditions. The Coulomb (1773) and the Rankine (1857) methods . Earth pressure due to the water, to overloads. Influence of the friction on the values of Active and passive earth preassure coefficients . Effect of the inclination of the campaign plan. Influence of the wall displacements. Presence of cohesion, critical height of a vertical wall. design of earth retaining walls under static and seismic loading conditions.
Settlements of direct foundations (1.25 cfu). Absolute and differential settlements. Admissible settlements for different types of structures. Immediate and consolidation settlements: primary and secondary consolidation settlements. Determination of the primary consolidation settlements, the EDOMETRIC settlement, the SKEMPTON-BJERRUM (1957) and Leonards (1976) approach. Determination of the secondary -consolidation settlements. Calculation of immediate settlements with the theory of elasticity. The presence of heterogeneous soils. The influence of the deepening of the laying plan and the rigidity of the foundation.
Bearing capacity of direct foundations (1.25 CFU). Stability analysis under ultimate and serviceability limit states.Types of failures of direct foundations. Bearing capacity under drained and undrained conditions. Prandtl (1921) and Terzaghi (1943) approaches. The Brinch-Hansen (1970) general equation. The influence of water level.
More information
e-mail nicola.moraci@unirc.it
Student reception: Friday 17-18