Geotechnics
Summary
Research in this research area encompasses a broad range of topics that include laboratory and field experimental testing programs, as well as analytical and numerical studies. The main research topics are: slopes and retaining systems, foundations and soil-structure interaction, field tests and instrumentation, earth work, environmental Geotechnics, pavements and soil stabilization, reinforced soils, soft soils, soil rheology, and rock mechanics.
Strong interaction with industry is an important characteristic of this research area. Several research projects are conducted in partnership with public agencies and private companies in topics that include: soil and rocky slope stabilization and retention in urban regions and highways; reinforced walls with geosynthetics in laboratory (physical models) and in the field; innovative, constructive solutions for embankments on very soft soils in urban areas, ports and highways; specialized laboratory and field geotechnical investigations with piezocone and vane equipment developed at COPPE; specialized monitoring of several works such as measures of strain in nailed soils and in geosynthetic reinforcements; consulting in special foundation works, onshore and offshore pipeline and raisers studies through centrifugal and numerical modeling; laboratory and field studies for highway and railway pavements; studies on soil contamination in cemeteries; diverse residue studies (urban solids, dredged sediments, mining); special technique using stabilized soil for bricks; innovative techniques for residue landfill casing and cover; soil and rock-fill dam studies, etc. Consequently, most of the research conducted at the Geotechnical Engineering area have directly influenced geotechnical engineering practice.
COPPE Geotechnical Engineering Laboratory occupies an area of around 2000 m2, comprising the following laboratories: soil strength and deformation tests, field tests and instrumentation, pavements, bituminous mixtures, asphalt binder rheology, soil chemistry and mineralogy, environmental geotechnics, physical modeling (drum centrifuge, 1G models and calibration chamber), solid wastes and rock mechanics.
Research Lines
Slopes and retaining systems
Slopes and soil and rock cuts are studied on this research line. The most aggressive movements are the quick ones called debris-flows, besides rock block falls and the erosion type that originate “vossorocas”. Another type of movement that particularly affects engineering works is the slow movement of saturated colluvial masses, generally with thickness greater than 5m in gentle slopes with less than 20º angles. Analysis techniques and design of general retaining structures are also studied on this research line. Researches comprise reinforced soil structures, including soil nailing and reinforced soil walls and slopes.
Foundations and soil-structure interaction
Some of the subjects approached on this research line are: prediction of settlements of shallow foundations by semi-empirical methods; prediction of deep foundation bearing capacity by theoretical and semi-empirical methods; pile static and dynamic behavior; study of time effects (creep and relaxation) on foundations; hybrid foundation behavior (associations between piles and spread footings or radiers); bearing capacity of piles under tensile loads; soil-structure interaction: study of structure-foundation combined behavior; behavior of open air excavations and tunnels.
Geotechnics research and Earth Works
General laboratory and field research techniques are studied on this line seeking to determine the characteristics of soil and rock materials and the geotechnical parameters used in deformation and stability analysis of geotechnical works. The Earth Works studied include general dams and embankments on soft soils from their design to performance evaluation through monitoring with geotechnical instrumentation. Studies comprise physical modeling in geotechnical centrifuge and finite element numerical modeling in onshore and offshore pipes.
Pavements and soil stabilization
Pavement mechanics applied to roads, airports, urban pavement and railroad pavements. Constitutive modeling using the finite element method. Theory of Viscoelasticity. Fracture Mechanics. Rheology applied to asphaltic materials. Experimental testing: (a) asphalt binders - traditional and Superpave tests; (b) soils and aggregates - resilient modulus, resistance to permanent deformation, and MCT; (c) asphalt mixtures - resilient modulus, dynamic modulus, resistance to fatigue cracking, permanent deformations, and moisture-induced damage. Mechanistic-empirical pavement design. Pavement evaluation. Maintenance and rehabilitation techniques using performance criteria defined through stress-strain analysis. Backanalysis of deflection basins. Recycling techniques using rejuvenating agents and foamed asphalt. Physical-chemichal properties of soils, Ki and Kr. Chemical stabilization of soils and use of industrial waste in pavements and bricks for popular dwellings.
Geotechnics in Environmental Projects
Researches on the relationship and impacts of climatic events and vegetation upon mass movements in natural slopes; geotechnical design and construction in Brownfield sites, prediction and risk control and potential impacts; influence of different types of inorganic and organic contaminants on geotechnical and hydraulic properties of soils; mechanical behavior (shear strength and compressibility) of different residues (solid urban wastes, dredged materials, mine wastes and others); waste stabilization and reuse in geotechnical engineering (C&D wastes, dredged sediments, fly and bottom ashes, slags, oil sludges, sludges from sewage and water treatments, and others); innovative solutions for covers and liners in land or subaquatic waste disposal structures, including geosynthetics; long term behavior investigation for waste deposits on land (landfills, dams, ponds, piles) from both geotechnical and environmental views; electrokinetics in soils and the relationship to the soils electrical, thermal, mechanical and hydraulic properties.