Optimising Landfill Settlement Prediction to Cater for Transport Infrastructure on Closed Landfills

Vinod, Michael

Optimising Landfill Settlement Prediction to Cater for Transport Infrastructure on Closed Landfills

Vinod, Michael

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Vinod, Michael
dc.date.accessioned	2023-07-14T00:39:37Z
dc.date.available	2023-07-14T00:39:37Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/171490
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	As urban development increases in major cities, there is an increasing trend in development above closed landfill sites. Waste mechanics and properties have been studied for decades by many researchers, and the current approach by practicing geotechnical engineers is heavily reliant on assuming parameters from the literature. However, due to the heterogeneous nature of waste, age, stiffness, climatic conditions, compaction, composition and variability among different landfill sites, the application of research studies towards assessing settlement from structures built above landfills is complex. This research is focussed on developing a practical and consistent approach utilising site investigation techniques and geotechnical laboratory testing to reasonably predict landfill settlement. The research is supported by a case study at a landfill in Sydney. The key field investigations undertaken included the collection of over 90 m of 100 mm diameter sonic drilling cores, test pitting over 5 tonnes of landfill, undisturbed and disturbed sampling for further testing in the laboratory, plate load testing, multi-channel analysis of surface waves (MASW), LIDAR and vertical seismic profiling. In this study, waste material, estimated to be aged between 18-31 years old, was collected from a landfill at a depth of 8 - 10 m using the sonic drilling technique. A multistage consolidated drained (CD) triaxial test was undertaken on a reconstituted sample to obtain design parameters for settlement prediction including friction angle, cohesion, modulus, compression indices (λ and κ), pre-consolidation pressure, over-consolidation ratio, permeability and long-term creep through constant stress creep and stress relaxation methods for the waste material. To demonstrate the benefits of undertaking site specific testing, settlement predictions were undertaken using existing 1D settlement prediction models and PLAXIS 2D. Predictions were validated with an embankment at the landfill that was instrumented using settlement cells and extensometers and monitored for a period of 2 years. Satellite monitoring using interferometric synthetic aperture radar (InSAR) was undertaken using the European Space Agency’s (ESA) Sentintel-1 satellite. The InSAR technique proved to be a low cost and effective method for long-term measurement of landfill settlement. Comparison of the settlement predictions using the field monitoring data and laboratory testing data exhibited a sound correlation with field monitoring data when initial settlement was corrected.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/171490/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Michael Vinod
dc.rights	au.edu.uts.lib/nph
dc.title	Optimising Landfill Settlement Prediction to Cater for Transport Infrastructure on Closed Landfills	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

As urban development increases in major cities, there is an increasing trend in development above closed landfill sites. Waste mechanics and properties have been studied for decades by many researchers, and the current approach by practicing geotechnical engineers is heavily reliant on assuming parameters from the literature. However, due to the heterogeneous nature of waste, age, stiffness, climatic conditions, compaction, composition and variability among different landfill sites, the application of research studies towards assessing settlement from structures built above landfills is complex. This research is focussed on developing a practical and consistent approach utilising site investigation techniques and geotechnical laboratory testing to reasonably predict landfill settlement. The research is supported by a case study at a landfill in Sydney. The key field investigations undertaken included the collection of over 90 m of 100 mm diameter sonic drilling cores, test pitting over 5 tonnes of landfill, undisturbed and disturbed sampling for further testing in the laboratory, plate load testing, multi-channel analysis of surface waves (MASW), LIDAR and vertical seismic profiling. In this study, waste material, estimated to be aged between 18-31 years old, was collected from a landfill at a depth of 8 - 10 m using the sonic drilling technique. A multistage consolidated drained (CD) triaxial test was undertaken on a reconstituted sample to obtain design parameters for settlement prediction including friction angle, cohesion, modulus, compression indices (λ and κ), pre-consolidation pressure, over-consolidation ratio, permeability and long-term creep through constant stress creep and stress relaxation methods for the waste material. To demonstrate the benefits of undertaking site specific testing, settlement predictions were undertaken using existing 1D settlement prediction models and PLAXIS 2D. Predictions were validated with an embankment at the landfill that was instrumented using settlement cells and extensometers and monitored for a period of 2 years. Satellite monitoring using interferometric synthetic aperture radar (InSAR) was undertaken using the European Space Agency’s (ESA) Sentintel-1 satellite. The InSAR technique proved to be a low cost and effective method for long-term measurement of landfill settlement. Comparison of the settlement predictions using the field monitoring data and laboratory testing data exhibited a sound correlation with field monitoring data when initial settlement was corrected.

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