The objective of this project is to investigate the ability of modern landfill waste containment systems to maintain their integrity when subject to waste settlement, earthquake loading, and loads from operational practices. The researchers will also examine design strategies and details to mitigate these potential threats to containment system integrity. Landfills are an essential component of our nation's civil infrastructure. Modern landfills rely upon sophisticated engineered liner and cover systems composed of soil and geosynthetic (i.e., polymer) materials to contain the waste and waste by-products and thereby protect the environment. A breach of a landfill containment system can result in serious and costly environmental impacts. While it is widely recognized that waste settlement can apply stress to landfill liner and cover systems, the impact of the large waste settlement typically associated with solid waste landfills on the integrity of these systems is generally not considered in current design practice. The impact of seismic loading on containment system integrity is generally considered in a gross empirical fashion; however, current methods do not quantify the loads applied by a seismic event to the containment system. Furthermore, damage that does occur to liner and cover system elements may be hidden, with no surface expression to alert the engineer, operator, owner, or regulator to the problem. The objectives of this collaborative research project will be achieved through: 1) experimental measurement of the load-deformation behavior of key geosynthetic/geosynthetic and geosynthetic/soil interfaces, including their response under dynamic loading, 2) development of realistic computational models that describe the load-deformation behavior of these elements and interfaces, 3) numerical implementation of the computational models to predict the behavior of waste containment systems subject to waste settlement and seismic loads, and 4) application of the numerical method to typical landfill configurations to identify conditions that pose a threat to the integrity of landfill liner and cover systems and develop strategies for mitigating these conditions.

This project has the potential to transform the way landfills are designed in engineering practice. The research conducted on this project is expected to lead to improved procedures for evaluating the integrity of landfill liner and cover systems; more realistic design methods; enhanced confidence in the long term reliability of landfills; improved landfill construction procedures; and, improved product design for geosynthetics used in landfill construction. The societal benefits of more realistic and reliable waste containment system designs should not be underestimated. Moving away from the crude and largely unsubstantiated design criterion currently used in practice and toward a more rational methodology will be a major advance in landfill design and help to enhance public acceptance of and confidence in waste containment systems. This project, funded in part under the Grant Opportunities for Academic Liaison with Industry (GOALI) program, is a collaboration between two industry/academia teams: Ohio State University and CETCO (a leading geosynthetic manufacturer) and Arizona State University and Geosyntec Consultants (a leading geoenvironmental consulting firm). The GOALI workshops proposed for the third year of the project will disseminate the research findings to a broad spectrum of stakeholders, including the USEPA, the California Integrated Waste Management Board and State Water Resources Control Board, geosynthetic manufacturers, landfill owners including major waste management firms and municipal governments, and environmental consulting firms.