Research: Geotechnical

The geotechnical group has a very strong research focus on environmental geotechnics and on fundamental understanding of geomechanics, covering a range of areas including:

• Fundamental Investigation of the Chemomechanical Properties of Clay
• Landfill & Solid Waste Management
• The Australian Alternative Cover Assessment Project
• Groundwater Contamination & Re-injection
• Land Application of Wastewater
• Mine Dewatering & Subsidence
• Reactive Walls
• Mine Tailings Placement & Stabilisation
• Earth-sheltered Domestic Structures

The geotechnical research group currently has 7 staff and 11 postgraduate students. Refer to the group's national competitive and industry grants and research publications.

A significant portion of the research is undertaken with collaborators in the Centre for Environmental and Applied Hydrology (CEAH).

An overview of some current research projects is outlined below. Prospective students are welcome to contact the geotechnical staff regarding these or other potential student projects. We invite students to undertake a research program leading to an Honours, Master or PhD qualification.

Fundamental Theoretical Investigation of the Chemomechanical Properties of Clay

The clay fraction of soils plays an important role in determining their behavior. In geotechnical engineering, the mechanical and chemical behavior of clays largely affects the strength and settlement characteristics of a loaded soil. There are several components in this project:

• Fundamentally understanding the hydraulic conductivity behavior of clayey soils.
• Understanding form the microscale to the macroscale the load-deformation behaviour of clay soils.
• Explaining residual friction angles.
• Understanding cavitation resistance of clayey soils.
• Understanding form the microscale to the macroscale swelling of clays and of other electrically charge materials.

Landfill & Solid Waste Management

The group is very active in a wide range of landfill related areas of research. These include:

• Landfill containment systems including alternative landfill covers
• Bioreactor landfills
• Landfill behaviours including settlements
• Landfill hydrology
• Solid waste management in developing countries
• Greenhouse emission from solid waste

The Australian Alternative Cover Assessment Project (A-ACAP)

This project is researching better ways of closing landfills, with particular reference to phytocaps. Phytocaps are covers of soil, typically between one and three metres thick, with plants growing on the surface. Phytocaps work to prevent rainfall from entering the underlying waste by harnessing water balance principles, instead of depending on reduced permeability, as is the case with conventional covers. The aim of A-ACAP is to determine quantitatively whether phytocaps can meet performance criteria for landfill final covers more cost effectively and sustainably than conventional covers, under a wide range of Australian conditions and jurisdictions. The purpose of the research is to address two key issues on which information for Australian conditions is currently unavailable, namely

• control of percolation of water into the waste zone (thereby reducing leachate and environmental impact) through the use of a plant cover selected on eco-climatic criteria, and
• reduction of atmospheric emissions of methane and other greenhouse gases and of odorous and volatile trace landfill gases.

The specific objectives of the project are to:

• collect and analyse scientific data that can be used to assist cost-effective and sustainable alternative cover designs for landfills
• establish and publish guidelines and criteria to be used by the solid waste management industry and regulatory agencies for the design, installation and monitoring of alternative covers; and
• improve scientific prediction of landfill cover performance under a wide range of Australian conditions.