Geoenvironmental Engineering Research

Research activities in Geoenvironmental Engineering at CSU primarily pertain to engineering aspects related to design, construction, and monitoring of containment facilities for a wide variety of waste disposal facilities (e.g., solid and hazardous waste landfills, impoundments, animal waste lagoons, evaporation ponds, etc.), as well as the development and evaluation of technologies for in situ remediation of subsurface contamination (e.g., in situ containment barriers, passive reactive barriers, stabilization and solidification, shallow and deep soil mixing, etc.). Current or recent research activities include the following:

  • evaluating the significance of clay membrane behavior (solute restriction, chemico-osmosis) on contaminant transport through barrier systems;
  • determining the long-term (2-3 year) hydraulic and mechanical performance of geosynthetic clay liners exposed to chemical solutions;
  • modeling the hydrologic water balance for alternative earthen covers used at waste disposal sites;
  • modeling the use of sulfate reducing bacteria in permeable reactive treatment trenches for precipitation of metals in acid mine drainage;
  • characterizing the mobility and fate of organic compounds existing as mixtures in the subsurface; and
  • evaluating the potential use of prefabricated vertical drains to accelerate the consolidation of in situ soils that have been mixed with zero-valent iron/clay slurries to treat contamination.

Additional research focus areas for graduate studies in Geoenvironmental Engineering at CSU typically consider issues such as the following:

  • effects of waste liquids on barrier material properties (compatibility);
  • containment strategies for emerging waste forms (e.g. nanowaste, pharmaceutical waste, animal waste (prions));
  • contaminant transport through low-permeability soil barriers;
  • development and evaluation of novel containment barrier materials;
  • development and evaluation of subsurface remediation technologies;
  • diffusion through polymer materials used as components of engineered barrier systems;
  • evaluation of flow and transport models for predicting barrier and remediation system performance;
  • geosynthetics for containment and remediation applications;
  • geotechnical aspects of waste containment and remediation systems;
  • leaching of contaminants from stabilized/solidified waste forms;
  • mine waste containment and remediation;
  • physical, chemical, and biological processes governing in situ remediation technologies;
  • physico-chemical interactions between soils and contaminant liquids (sorption, ion exchange; and
  • unsaturated flow through soil covers used for waste disposal

Geotechnical Engineering Research

Research activities in Geotechnical Engineering at CSU are focused in a variety of areas, from fundamental to applied research, and from experimental to theoretical research. Fundamental research includes basic aspects of soil mechanics, such as the experimental determination of the physical and mechanical properties of geological, geosynthetic, and waste materials used in civil engineering applications under both saturated and unsaturated conditions. Applied research refers to studies that are directly applicable to engineering practice. Experimental research is performed at both the laboratory and the field scales. Laboratory experimental research typically is associated with the fundamental characterization of geomaterials, whereas field experimental research is more typically applied research. Theoretical research pertains to the development of new theories to describe the fundamental behavior of geomaterials or the evaluation of existing theories of geomaterial behavior, typically expressed in the form of analytical or numerical models.

Examples of recent and current research activities in Geotechnical Engineering at CSU include the following:

  • determination of physical and mechanical properties of geomaterials, e.g., natural soils, tailings and mine waste, and non-hazardous solid waste;
  • development and evaluation of new geomaterials and beneficial reuse of waste materials, e.g., soil-bentonite mixtures, fly ash amended soils, and co-mixed tailings and waste rock;
  • characterization of the stress-strain response of soils using triaxial apparatuses;
  • determination of the effect of soil fabric and anisotropy on soil behavior;
  • development of new and innovative experimental methods for laboratory testing of geomaterials;