Modelling of post-closure behaviour for municipal solid waste landfills: Settlement and slope stability
- Autores: Li Yu
- Directores de la Tesis: Jesús Carrera Ramírez (dir. tes.), Francisco Batlle Pifarré (codir. tes.), Daniel Fernández García (tut. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2011
- Idioma: inglés
- Tribunal Calificador de la Tesis: Francisco Javier Elorza Tenreiro (presid.), Sebastià Olivella Pastallé (secret.), César Sagaseta Millán (voc.), Antonio Lloret Morancho (voc.), Dirk Mallants (voc.)
- Materias:
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- Resumen
Sanitary landfilling is lhe most economic method for lhe disposal ofmunicipal solid waste (MSW). Once lhe waste is deposited. organic solids contained in lhe waste begin to biodegrade and continuouslygenerate landfill gas. Hence.longterm seltlement ofMSWlandfill exhibits both mechanical and biological components, so lhat MSW landfills behave like dynamic systems. Therefore, topies related to post-closure seltlement and slope stability, which are ofmajor concern lo geotechnical engineers, do notfullow conventional geotechnies laws. This studyaims to investigate hydro-mechanical (HM) behaviour ofMSW landfills and provide solutions to various aspects related to landfill design and operation.
After investigating lhe seltlemenl mechanism ofwaste and clarifying the relationship between mechanical and biodegradation induced settlements, lhe effect ofwasle degradation on seltlemenl was implicitly incorporated into a K-H rheological seltlement model, which was then applied to several topies relaled to post-closure behaviour ofMSWlandfill: Temporal and spatial variations in unitweightoflhe MSWwere estimated byconsidering the defermation ofthe waste matrix, which includes both shorl- and long-term mechanical effects, and mass los s caused bywaste degradation.
Typical parameter values were obtained lor representative MSWlandfills. The results reveal different variation Irends olwaste unitweight in lhe upper and lower portions (chapter 2).
One-dimensional seltlement fer multi-Iayered MSWlandfills was predicted analyticallyconsidering lhe interactions between the gas phase and lhe solid phase. The model reproduced bolh the time evolution ofseltlement and gas flux in horizontallandfill gas collection systems (chapter 3).
Two-dimensional radial gas flow to a vertical gas extraction well in deformable MSW landfills was simulated analytically. The analytical solution shows thatthe economical optimum results Irom balanclng imposed vacuum, well distance and cover properties (chapter 4).
A hybrid method fur quasi-three-dimensional slope stabilityanalysis was proposed fer dynamic evaluations 01 slope stabilityata MSWlandfil1. Application oflhe model indicates Ihatthe melhod can serve as an engineering tool in preliminary estimates ollhe s afety factor and lhe position and extent oflhe potential slide mass (chapter 5).
Numerical simulations 01 a long-duration pumping test wilh variable pumping rate at a MSWlandfill were carried out to investigate lhe HM behaviour and determine lhe hydraulic parameters olwaste. The hydraulic conductivitywas found varying between 4.5xl0-7 - 5.5x10-6 mis with an anisotropic ratio 0110 (chapter 6).
Research work carried out on a varietyoftopies enhanced lhe overall understanding olthe post-closure behaviour ofthe MSW landfill. Model predictions compared well wilh field measurements in terms olunit weight, long-term seltlement and gas extraction Irom wells, which proves the applicability01 lhe proposed models in MSWlandfills. The obtained waste parameters will help engineers in the design and operation 01 MSWlandfills.
