Geosystems Engineering
Faculty | Courses | Facilities | Research
Geosystems Engineering involves the characterization and utilization of natural geomaterials on their own or in combination with man-made materials for use in engineered systems and includes the related but distinct disciplines of geotechnical engineering, geomechanics, geomaterials, and environmental geotechnics. Accordingly, the scope of the discipline has expanded today to include a broad range of topics including: shallow and deep foundation design; slope stability; tunnels and trenchless technologies; excavation support systems; reinforced retaining structures; construction and rehabilitation of earth dams; natural and man-made hazard mitigation; advanced techniques for site and material characterization; constitutive modeling of geomaterials; design of advanced pavement systems; ground modification; and geo-environmental assessment and remediation.
Working with natural materials is a challenging task due to their inherent variability and complexities. Consequently, experimental, theoretical, empirical, and probabilistic tools are used for evaluating subsurface conditions. Both destructive and nondestructive tests performed in situ or on laboratory samples have been developed for measuring the engineering properties of natural materials under a wide range of boundary conditions. Analytical methods have similarly advanced to enable increasingly complex systems and loading environments to be effectively modeled.
The faculty have varied backgrounds, rich in practical experience, strong in their understanding of theoretical mechanics and fundamental physical processes and are internationally recognized for their contributions in both experimental and numerical assessment and modeling of geomaterials. The diverse backgrounds of the faculty enables a comprehensive course curriculum and a broad range of research opportunities to be offered to incoming graduate students.
Current research projects include liquefaction susceptibility assessment using seismic tomography, quantification of soil structure using digital image analysis, development of advanced piezocone profiling systems, fundamental microscale study of particulate materials and processes, constitutive modeling of soil behavior, nondestructive evaluation of infrastructure components, earthquake hazard prediction using geographic information systems, analytical and numerical fracture mechanics, flow of fluids in the earth’s crust, study of induced seismicity, prediction of asphalt pavement performance, and modeling of underground openings and structures. Faculty members in the group are extensively involved in the NSF sponsored Mid-America Earthquake Center, the State supported Georgia Transportation Institute and the industry supported Center for Applied Geomechanics Research.
Between 50 and 60 graduate students are enrolled each year. Approximately 50% of the graduate students are Ph.D. candidates. In addition, about 10 undergraduate students are involved in research projects. All students are members of the Georgia Tech Geotechnical Society, a student-organized society that organizes and hosts academic and social activities for students and faculty.
Geosystems Engineering Faculty Information [ Return to top ]
Geosystems Engineering Courses [ Return to top ]
Undergraduate Course Information
Civil Engineering Materials
Physical, mechanical and durability properties of concrete, metals, unreinforced and reinforced plastics, timber, geomaterials, asphalt and asphalt concrete.
Geosystems Engineering
Introduction to engineering behavior of soils including mechanical, chemical, electrical and thermal properties; continuum design principles based on theory of elasticity and limiting equilibrium methods applied to particulate soil systems.
Geosystems Engineering Design
Analysis and design in geosystems engineering projects, including evaluation of shallow footings, pile foundations, natural and man-made slopes, earth retaining structures, and embankments.
Subsurface Characterization
Introduction to field and laboratory methods for characterizing subsurface geological, hydrological, geotechnical and contaminant conditions.
Graduate Course Information
Soil Mechanics
Fundamental concepts related to the engineering behavior of soils including: effective stress, strength, stiffness, permeability, time-dependent behavior.
Laboratory Characterization of Geomaterials
Instruction in the procedures, methods of interpretation and apparatus limitations and influences for geotechnical laboratory index, strength, deformation and permeability tests.
Experimental Methods in Soil Behavior
Experimental study of geomaterials and geoprocesses. Emphasis on micro-scale phenomena. Topics include scale effects, similarity, falsification, design of experiments, errors, transducers.
In-Situ Testing and Site Characterization of Geomaterials
Field testing and sampling of geomaterials, primarily soils and rocks. Methods of drilling, probing, and measurement for determining stratigraphy and engineering parameters, including soil borings, in situ piezoconecone penetration, pressuremeter, dilatometer and other tests.
Analysis of Earth Structures
Instruction in analytical techniques for assessing the stability of earth retaining structures including unreinforced slopes, reinforced slopes, free standing retaining structures and reinforced retaining structures.
Dynamic Analysis in Geotechnical Engineering
Dynamic soil properties; response of foundations to dynamic loads; construction and blast vibration criteria; dynamic analysis of pile driving; introduction to liquefaction potential.
Foundation Systems
Evaluation and design of foundations, including settlement and bearing capacity of shallow spread footings, mats, and deep foundations using elastic continuum theory, limit plasticity, and cavity expansion solutions, supplemented with numerous case studies.
Geotechnical Earthquake Engineering
Earthquake magnitude and intensity, seismic hazard evaluation using deterministic and probabilistic approaches, site response analyses and ground motion amplification, liquefaction, and response of earth structures.
Pavement Design
Analysis and design of flexible and rigid pavement for highway and airfield runway, evaluation of pavement performance and distress, and pavement rehabilitation strategy and techniques.
Rock Mechanics
Rock characterization, scale effect, in situ stresses, mechanisms of rock deformation and fracture, rock engineering.
Mathematical Applications for Civil and Environmental Engineering
Mathematical techniques are reviewed in the context of CEE problems. The simplified yet mathematically rigorous approach highlights the internal mathematical connections between different engineering problems including extensive usage of computer algebra.
Signals and Inverse Problems in Civil Engineering
Civil engineering signals and systems. Discrete time and frequency domain operations. Non-linear and non-stationary systems. Inverse problems. Matrix-based and other solutions. Tomographic imaging.
Constitutive Modeling of Soils
Elassticity and Hyperelasticity; Hypoelasticity and Anisotropy; Plasticity and Hyperplasticity; Classical Plasticity Models; Non-associated Plasticity; Cap Models; Critical State Models; Viscoelasticity and Viscoplasticity; Introduction into Advanced Plasticity.
Applied Fracture Mechanics
Application of fracture mechanics on practical civil engineering problems. General fracture behavior studied in the context of a variety of applied topics. Computer and experimental demonstrations.
Geotechnical Image and Spatial Analysis
Presentation of techniques for spatial and image processing and analysis of subsurface data at micro and macro scales. Mathematical morphology. Surface characterization. Soil structure evolution.
Wave-based Characterization of Particulate Materials
Characterization of materials with mechanical and electromagnetic waves. Evaluation of inter-particle forces. Fabric and interval spatial and temporal scales. Laboratory and field geophysical methods and applications.
Physical Properties and Rheology of Rocks
Structure, properties, and rheology of minerals and rocks with applications to engineering structures and natural phenomena in the earth. Fundamentals of rock mechanics and crack propagation.
Additional graduate courses on special topics are also offered periodically.
Geosystems Engineering Facilities [ Return to top ]
The Geosystems Engineering instruction and research laboratories occupy over 10,000 square feet of custom space within the Mason Civil Engineering Building and include the George F. Sowers Soil Mechanics Instruction Laboratory, the Particulate Media Research Laboratory, the Rock and Fracture Mechanics Laboratory, the Earth and Manufactured Materials Research Laboratory, the Geomaterial Surface and Structure Characterization Laboratory, the Site Characterization Laboratory, the Near-Surface Geophysics Laboratory, the Asphalt Technology Laboratory and the Environmental Geotechnics Laboratory. As a complement to the main campus library, the Geosystems Engineering Robnett Library houses an extensive collection of books, conference proceedings and technical journals.
The George F. Sowers Soil Mechanics Instruction Laboratory is equipped with an extensive range of devices for conducting routine classification and index tests. In addition, the laboratory houses a range of devices for measuring the compressibility, strength and hydraulic conductivity characteristics of soils. In particular, the laboratory is equipped with five integrated test stations, each consisting of a computer-controlled load frame, a pressure control panel, multiple test cells and a data acquisition system which includes a microcomputer, signal conditioning hardware and data acquisition/reduction software. Each station can be configured to permit triaxial, consolidation, hydraulic conductivity, unconfined compression and CBR testing as desired.
The Earth and Manufactured Materials Research Laboratory is equipped with a large vertical displacement stylus profilometer system. Testing of geosynthetic materials can be performed using a large pullout box. Strength and deformation response of soil and/or geosynthetic samples can be evaluated in a 12-inch square direct/interface shear device capable of normal and shear loads of 30 kips. A 2.8 in. diameter direct/interface shear device is used for testing smaller specimens.
The Particulate Materials Research Laboratory is equipped to conduct micro-scale experimental studies, atomic force microscopy, specific surface and pore size distribution by gas absorption, broad-band measurements and process monitoring with both mechanical waves (10 Hz to 50 kHz) and electromagnetic waves (5 Hz to 1.3 GHz) in a variety of devices and cells (axisymmetric, Ko cells and mid-size cubical triaxial) and scaled tomographic studies.
The Geomaterial Surface and Structure Characterization Laboratory includes facilities for static and dynamic testing of soil specimens, for cutting, grinding and polishing surfaces of various geomaterials and for capturing optical images for processing and analysis. In particular, static and dynamic tests can be performed with a CKC automated triaxial testing system. Dynamic properties can be determined with a Stokoe resonant column device and a hybrid resonant column/torsional shear device which permits the determination of soil properties on a solid or hollow cylinder specimen over a wide range of strain amplitudes. The device can be used to perform tests on specimens up to 10 inches in diameter and thus is suitable for testing gravels. A full-size x-ray facility is also available for non-destructive evaluation of soil specimens and scale models. Apparatus for preparation of surfaces for optical imaging includes a range of diamond saws and grinders/polishers. Image analysis for studies of surfaces and soil structure is possible with several image analyses systems. A cluster of 6 Silicon Graphics workstations are used for spatial subsurface hazard analysis.
The Environmental Geotechnics Laboratory is equipped to assess hazardous subsurface conditions. The laboratory infrastructure includes 6- and 10- square foot vacuum hoods, an independent thermal exhaust system, and a water purification and de-aeration system. Laboratory equipment includes two-dimensional tanks, and banks of triaxial permeameters and geochemical columns to evaluate fate and transport of organics and metals. Each apparatus is linked to a computer-controlled pressure data acquisition system. A microcomputer controlled gas chromatograph equipped with an autosampler, flame ionization and thermal conductivity detectors is available for organics analysis. Dilute and concentrated metals analyses can be conducted using an inductively coupled plasma mass spectrometer and a fully interchangeable atomic adsorption graphite furnace. Both instruments have autosamplers and are microcomputer controlled. Other available equipment includes a portable water quality probe, countertop pH, eH, and conductivity probes, a semiautomatic tensiometer for measuring interfacial tension, single and mutli-channel peristaltic pumps, and a dual camera video recording system to film hydrocarbon fate, transport and recovery experiments involving dyed liquids.
The Site Characterization Laboratory is equipped with a cone penetration truck which includes an earth anchoring system and integrated field data acquisition system that can be used for conducting in situ site investigations to depths exceeding 35 meters in soils. In situ measurements can be made with a full range of test devices including electric cone penetrometers, flat plate dilatometers, pressuremeters, piezocones, and downhole geophysical measurements. Specialized devices for research include a resistivity module, dielectric penetrometer, dual-element piezocone, piezo- vibrocone for direct assessment of soil liquefaction potential and post-cyclic residual undrained strength.
The Near-Surface Geophysics Laboratory has equipment available to perform a variety of seismic and electromagnetic geophysical tests for subsurface characterization of geologic, hydrologic and environmental conditions. Active and passive measurements of surface wave dispersion and attenuation are conducted using a multi-channel data acquisition system, a 100-lbf electromechanical source, and 1-Hz geophones. Borehole devices including an in-hole mechanical source and two triaxial geophones are used for cross-hole and down-hole tests. Down-hole tests can also be performed using a seismic cone penetrometer. Non-destructive evaluations of foundation performance and integrity can be conducted with an instrumented hammer and piezoelectric accelerometers. The laboratory also has a ground penetrating radar, an electromagnetic conductivity system, a proton precession magnetometer and a soil resistivity system available for non-invasive environmental site characterization.
The Asphalt Technology Laboratory includes facilities for evaluating asphalt binder properties, and for performing hot mix asphalt mixture design. The laboratory is also equipped with a Georgia Loaded Wheel Tester and a companion rolling compacting machine, which were developed for evaluating rutting and fatigue characteristics of asphalt mixtures.
Geosystems Engineering Research [ Return to top ]
The Geosystems Engineering Research program involves about 60 graduate and 10 undergraduate students supervised by eight full-time faculty. Two professional staff members provide support in the laboratory for the research activities. An extensive research program is being undertaken with support from the National Science Foundation, Federal Highway Administration, US Geological Survey, Georgia Department of Transportation, Environmental Protection Agency, U.S. Air Force, U.S. Army and private industry. The principal thrust areas of research are Material Characterization and Soil Behavior, Civil Infrastructure and Foundation Systems, Soil Dynamics and Earthquake Engineering, Mining and Petroleum Geomechanics, and Environmental Geotechnics. An summary of activities in these thrust areas is provided below.
Material Characterization and Soil Behavior
A thorough understanding of material behavior is critical to ensuring cost-effective, well-engineered systems are constructed on and/or with geomaterials. A significant portion of the research being conducted at Georgia Tech is focussed on experimental study of micro-scale phenomena and relating this to observed macro-scale response of geotechnical systems.
- Digital image processing and analysis is being used to study the initial and evolving micro-structure of reconstituted and naturally deposited sands.
- Optical and atomic force microscope images are being used to quantify the surface roughness of various commonly used synthetic materials.
- Research to investigate the viability of using high strength/high performance concrete for bridge construction is being conducted.
- Electromagnetic parameters are being used to provide microscale information about the polarizability (dielectric permittivity) of fine grained high specific surface materials and the ability of charges to move (electrical conductivity).
- Internal processes are being identified and studied at the particle level to try and explain phenomena such as changes in effective stress and in the Coulomb failure criterion, small strain stiffness and losses, and threshold strain.
- Energy loss mechanisms in particulate materials including viscous processes, frictional processes, and other coupled energy processes are being studied at the micro-scale using atomic force microscopy and stochastic resonance techniques to explain macro-scale observations.
- Changes in the microstructure of concrete due to high velocity penetrator impacts are being quantified using optical imaging techniques.
- The surface topography of construction materials is being characterized using stylus profilometry techniques.
Civil Infrastructure and Foundation Systems
Much of the nations civil infrastructure is in need of assessment and rehabilitation. Research being conducted at Georgia Tech is aimed at ensuring that techniques for effectively assessing infrastructure degradation exist. Equally importantly, research is also being conducted to ensure that next-generation infrastructure is optimally designed.
- An extensive research effort to improve the prediction of the performance of asphalt mixture using the Georgia Loaded Wheel Tester is being undertaken.
- The Georgia Loaded Wheel Tester is being used to evaluate the permanent deformation characteristics of the asphalt mixtures used for constructing 26 test sections in the WesTrack Road Test Project in Nevada.
- Methods for designing and predicting the behavior of geotechnical interfaces for various infrastructure applications using surface characterization and geotribology are being developed.
- An asphalt pavement evaluation and rehabilitation expert system to facilitate maintenance programming is being developed.
- Ongoing research is investigating the use of a seismic cone penetrometer and a seismic flat dilatometer to provide determinations of both the low and high strain behavior of soils within a single sounding.
- The potential use of fiber-reinforced polymers in single and group pile foundations is currently being investigated with experimental and analytical studies.
- A nondestructive test method based on modal analysis of flexural wave propagation is being developed to determine unknown pile tip elevations.
- A new multi-sleeve attachment for the cone penetration test which can lead to improved friction pile design methodologies is being developed and evaluated.
Soil Dynamics and Earthquake Engineering
Natural hazards such as earthquakes impose significant additional loads on systems that are operating adequately under normal conditions. Research at Georgia Tech is leading to new methods to reliably predict the consequences of such events for existing facilities as well as identify how the consequences of future events can be reduced.
- A new in situ testing device to assess directly the soil liquefaction potential during seismic events as well as the post-cyclic loading undrained residual strength of silty and sandy soils is being developed.
- Seismic piezo-cone penetration tests are being performed at carbon-dated geologically-mapped paleo-liquefaction sites having sand dikes, subsidence features, and other liquefaction evidence.
- The potential for CPT to be used as a stand-alone tool for liquefaction assessment by using friction sleeve and/or penetration porewater pressure measurements and tip resistance is being investigated.
- Research to develop systems that incorporate methodologies for evaluating geotechnical earthquake hazards in a spatial analysis environment is being undertaken.
- A combined resonant column-torsional shear apparatus suitable for testing materials with larger particles including gravels is being used to develop a better understanding and framework for predicting variations in shear modulus and damping as a function of applied shear strain.
- An in situ seismic method that utilizes passive measurements of surface waves arising from micro-tremors and/or cultural noise such as traffic is being developed.
- Research using remotely sensed data to obtain or infer dynamic soil property data to allow for more accurate NEHRP site classifications for states in the New Madrid Seismic Zone is being undertaken.
- A study to develop and evaluate a procedure for simultaneously determining both the shear modulus and damping ratio profiles from surface wave measurements is being undertaken.
- Standard methods of selecting and mounting transducers, processing vibration data, and interpreting test results from man-made vibrations are being studied.
- Techniques for ground improvement for existing essential facilities subjected to seismic loading are being evaluated.
- Optical imaging and small strain measurements are being used to study the role of local defects in the genesis and evolution of sand blows.
Mining and Petroleum Geomechanics
The recovery of natural materials can result in significant changes in the subsurface physical, chemical, electrical and thermal conditions. Research at Georgia Tech is examining how the recovery processes induce these changes as well as how their impacts can be minimized.
- Three-dimensional numerical models for crack growth and interaction in compression are being developed and tested.
- A method of inducing internal three-dimensional cracks of given number, size, and orientation for use in laboratory fracture experiments is being developed.
- Research to improve fundamental understanding of mechanisms and factors affecting hydraulic fracture processes is being conducted.
- Simple conceptual physical and numerical experiments that elucidate and visualize fundamental mechanisms of sand production are being designed and conducted.
- Research to investigate the fundamental mechanisms of borehole instability in anisotropic formations that influence instability prediction and control is being undertaken.
- The various mechanisms that are common to hydraulic fracturing in seabed sediments and depend on the treatment conditions, rock characteristics, and in situ stress fields are being studied.
- Research to identify the conditions whereby subsurface fluid withdrawal can cause reactivation of a near-by fault with sufficient slip for excavation shearing and seismic impact on surface structures is being undertaken.
- Numerical models are being used to study hydrothermal venting on the ocean floor and understand the observed heat and fluid fluxes in the ridge crest hydrothermal system generated by such coupled processes.
- Acoustic and electromagnetic waves are being monitored to provide complementary information about internal processes and the characteristics of materials being mined.
- The manner in which surface alteration can significantly change the micro-scale and macro-scale properties of particulate materials and hence their fabric and engineering properties is being evaluated.
- The effect of discontinuities on the small-strain velocity and attenuation within particulate media is being examined using a unique column experiment device.
- Research involving transducer design and installation, tomographic imaging of the state of stress in soils and tomographic imaging of anomalies is being conducted.