Matching Items (3)
Description
A method for evaluating the integrity of geosynthetic elements of a waste containment system subject to seismic loading is developed using a large strain finite difference numerical computer program. The method accounts for the effect of interaction between the geosynthetic elements and the overlying waste on seismic response and allows for explicit calculation of forces and strains in the geosynthetic elements. Based upon comparison of numerical results to experimental data, an elastic-perfectly plastic interface model is demonstrated to adequately reproduce the cyclic behavior of typical geomembrane-geotextile and geomembrane-geomembrane interfaces provided the appropriate interface properties are used. New constitutive models are developed for the in-plane cyclic shear behavior of textured geomembrane/geosynthetic clay liner (GMX/GCL) interfaces and GCLs. The GMX/GCL model is an empirical model and the GCL model is a kinematic hardening, isotropic softening multi yield surface plasticity model. Both new models allows for degradation in the cyclic shear resistance from a peak to a large displacement shear strength. The ability of the finite difference model to predict forces and strains in a geosynthetic element modeled as a beam element with zero moment of inertia sandwiched between two interface elements is demonstrated using hypothetical models of a heap leach pad and two typical landfill configurations. The numerical model is then used to conduct back analyses of the performance of two lined municipal solid waste (MSW) landfills subjected to strong ground motions in the Northridge earthquake. The modulus reduction "backbone curve" employed with the Masing criterion and 2% Rayleigh damping to model the cyclic behavior of MSW was established by back-analysis of the response of the Operating Industries Inc. landfill to five different earthquakes, three small magnitude nearby events and two larger magnitude distant events. The numerical back analysis was able to predict the tears observed in the Chiquita Canyon Landfill liner system after the earthquake if strain concentrations due to seams and scratches in the geomembrane are taken into account. The apparent good performance of the Lopez Canyon landfill geomembrane and the observed tension in the overlying geotextile after the Northridge event was also successfully predicted using the numerical model.
ContributorsArab, Mohamed G (Author) / Kavazanjian, Edward (Thesis advisor) / Zapata, Claudia (Committee member) / Houston, Sandra (Committee member) / Arizona State University (Publisher)
Created2011
Description
It is widely recognized that, compared to others, minority and low-income populations are more exposed to environmental burdens and unwanted land uses like waste facilities. To prevent these injustices, cities and industry need to recognize these potential problems in the siting process and work to address them. I studied Phoenix, AZ, which has historically suffered from environmental justice issues. I examined whether Phoenix considered environmental justice concerns when siting their newest landfill (SR-85) and transfer station (North Gateway Transfer Station). Additionally, I assessed current views on sustainability from members of the Phoenix Transportation and Infrastructure Subcommittee and of decision-makers in the Public Works Department and Solid Waste Division. Using a mixed methods approach consisting of interviews, document analysis, and a demographic assessment of census tracts, I addressed two main research questions:
1. Do the distributions and siting processes of environmental burdens from SR-85 and North Gateway Transfer Station constitute a case of environmental injustice according to commonly held definitions?
2. Do current Solid Waste and council members on the Transportation and Infrastructure subcommittee consider environmental justice, defined as stakeholder engagement, to be a part of sustainability?
The results show that the distribution and siting processes of environmental burdens from these facilities may constitute a case of environmental injustice. While city officials do involve stakeholders in siting decisions, the effects of this involvement is unclear. An analysis of long-term demographic data, however, revealed no significant racial, ethnic, or economic effects due to the locations of the SR-85 and North Gateway Transfer Station.
Interviews with current members of the Transportation and Infrastructure Subcommittee, Public Works Department, and Solid Waste Division indicated that Phoenix’s decision-makers don’t consider environmental justice as part of sustainability. However, they seem to consider stakeholder engagement as important for decision-making.
To help mitigate future injustices, Phoenix needs buffer zone policies for waste facilities and stakeholder engagement policies for decision-making to ensure the public is engaged appropriately in all circumstances. Enacting these policies will help Phoenix become both a more sustainable city and one in which stakeholders have the opportunity to provide feedback and are given decision-making power.
1. Do the distributions and siting processes of environmental burdens from SR-85 and North Gateway Transfer Station constitute a case of environmental injustice according to commonly held definitions?
2. Do current Solid Waste and council members on the Transportation and Infrastructure subcommittee consider environmental justice, defined as stakeholder engagement, to be a part of sustainability?
The results show that the distribution and siting processes of environmental burdens from these facilities may constitute a case of environmental injustice. While city officials do involve stakeholders in siting decisions, the effects of this involvement is unclear. An analysis of long-term demographic data, however, revealed no significant racial, ethnic, or economic effects due to the locations of the SR-85 and North Gateway Transfer Station.
Interviews with current members of the Transportation and Infrastructure Subcommittee, Public Works Department, and Solid Waste Division indicated that Phoenix’s decision-makers don’t consider environmental justice as part of sustainability. However, they seem to consider stakeholder engagement as important for decision-making.
To help mitigate future injustices, Phoenix needs buffer zone policies for waste facilities and stakeholder engagement policies for decision-making to ensure the public is engaged appropriately in all circumstances. Enacting these policies will help Phoenix become both a more sustainable city and one in which stakeholders have the opportunity to provide feedback and are given decision-making power.
ContributorsGarland, P. M. (Patricia M.) (Author) / Golub, Aaron (Thesis advisor) / Boone, Christopher (Committee member) / Kim, Yushim (Committee member) / Arizona State University (Publisher)
Created2015
Description
The objective of the research is to develop guidelines for identifying when settlement or seismic loading presents a threat to the integrity of geosynthetic elements for both side slope and cover systems in landfills, and advance further investigation for parameters which influence the strains in the barrier systems. A numerical model of landfill with different side slope inclinations are developed by the two-dimensional explicit finite difference program FLAC 7.0, beam elements with a hyperbolic stress-strain relationship, zero moment of inertia, and interface elements on both sides were used to model the geosynthetic barrier systems. The resulting numerical model demonstrates the load-displacement behavior of geosynthetic interfaces, including whole liner systems and dynamic shear response. It is also through the different results in strains from the influences of slope angle and interface friction of geosynthetic liners to develop implications for engineering practice and recommendations for static and seismic design of waste containment systems.
ContributorsWu, Xuan (Author) / Kavazanjian, Edward (Thesis advisor) / Zapata, Claudia (Committee member) / Houston, Sandra (Committee member) / Arizona State University (Publisher)
Created2013