Seismic stability analyses of reinforced tapered landfill cover systems considering seepage forces

2018 ◽  
Vol 36 (4) ◽  
pp. 361-372 ◽  
Author(s):  
Afshin Khoshand ◽  
Ali Fathi ◽  
Milad Zoghi ◽  
Hamidreza Kamalan
Keyword(s):  
Parametric Study ◽  
Limit Equilibrium ◽  
Practical Method ◽  
Seismic Stability ◽  
Design Parameters ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System ◽  
The Stability

One of the most common and economical methods for waste disposal is landfilling. The landfill cover system is one of the main components of landfills which prevents waste exposure to the environment by creating a barrier between the waste and the surrounding environment. The stability and integrity of the landfill cover system is a fundamental part of the design, construction, and maintenance of landfills. A reinforced tapered landfill cover system can be considered as a practical method for improving its stability; however, the simultaneous effects of seismic and seepage forces in the reinforced tapered landfill cover system have not been studied. The current paper provides a solution based on the limit equilibrium method in order to evaluate the stability of a reinforced tapered landfill cover system under seismic and seepage (both horizontal and parallel seepage force patterns) loading conditions. The proposed analytical approach is applied to different design cases through parametric study and the obtained results are compared to those derived from literature. Parametric study is performed to illustrate the sensitivity of the safety factor (FS) to the different design parameters. The obtained results reveal that parameters which describe the geometry have limited effects on the stability of the landfill cover system in comparison to the rest of the studied design parameters. Moreover, the comparisons between the derived results and available methods demonstrate good agreement between obtained findings with those reported in the literature.

Simulation of Final Cover Systems in Mitigating Landfill Gas Migration

2014 ◽  
Vol 587-589 ◽  
pp. 886-891
Author(s):  
Thaveesak Vangpaisal
Keyword(s):  
Barrier Layer ◽  
Landfill Gas ◽  
Element Model ◽  
Effective Control ◽  
Gas Migration ◽  
Gas Flux ◽  
Cover System ◽  
Landfill Cover ◽  
Cover Systems ◽  
Landfill Cover System

Landfill cover systems have to serve as a hydraulic barrier as well as a gas barrier. The ability of multilayered cover systems to mitigate landfill gas migration was assessed. A finite element model, SEEP/W®, was used to simulate the landfill cover system. It was found that gas advective flux through the single GCL barrier was highly dependent on the differential gas pressure across the cover system and the conditions of soils above the barrier layer. The change from wet to dry condition resulted in the increase of gas flux up to 3000 times. Gas flux variations were much lower for the case of a single CCL. The use of a geomembrane on top of a CCL or a GCL significantly increased the effectiveness of the barrier layer in mitigating gas migration, particularly in a dry climatic condition. Furthermore, the change of the cover conditions had less effect on gas flux through a composite cover system than gas flux through a single barrier cover system. For the effective control of landfill gas migration, the cover system must be maintained at the high moisture content conditions.

The potential application of red mud and soil mixture as additive to the surface layer of a landfill cover system

2016 ◽  
Vol 44 ◽  
pp. 189-196 ◽  
Author(s):  
Éva Ujaczki ◽  
Viktória Feigl ◽  
Mónika Molnár ◽  
Emese Vaszita ◽  
Nikolett Uzinger ◽  
...  
Keyword(s):  
Surface Layer ◽  
Red Mud ◽  
Potential Application ◽  
Soil Mixture ◽  
Cover System ◽  
Landfill Cover ◽  
Landfill Cover System

Characterization of methane oxidation in a simulated landfill cover system by comparing molecular and stable isotope mass balances

2017 ◽  
Vol 69 ◽  
pp. 281-288 ◽  
Author(s):  
Marcel Schulte ◽  
Maik A. Jochmann ◽  
Tobias Gehrke ◽  
Andrea Thom ◽  
Tim Ricken ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Methane Oxidation ◽  
Mass Balances ◽  
Cover System ◽  
Landfill Cover ◽  
Landfill Cover System ◽  
Simulated Landfill

Water Infiltration into a New Three-Layer Landfill Cover System

2016 ◽  
Vol 142 (5) ◽  
pp. 04016007 ◽  
Author(s):  
Charles W. W. Ng ◽  
Jason L. Coo ◽  
Zhong Kui Chen ◽  
Rui Chen
Keyword(s):  
Water Infiltration ◽  
Cover System ◽  
Landfill Cover ◽  
Landfill Cover System

scholarly journals ESTUDO DE VIABILIDADE TÉCNICA DO FOSFOGESSO HEMIDRATADO PARA APLICAÇÃO EM SISTEMA DE COBERTURA DE ATERROS SANITÁRIOS [ Study of the phosphogypsum hemidrate for application in a landfill cover system ]

2018 ◽  
Vol 14 (2) ◽  
Author(s):  
Matheus Eliatan da Silva Ribeiro ◽  
Márcia Maria dos Anjos Mascarenhas ◽  
Thiago Lopes dos Santos
Keyword(s):  
Seasonal Variations ◽  
Industrial Production ◽  
Low Permeability ◽  
Seasonal Cycles ◽  
Wetting And Drying ◽  
Cover System ◽  
Landfill Cover ◽  
Acceptable Range ◽  
Compaction Energy ◽  
Landfill Cover System

RESUMO: O fosfogesso (CaSO4.nH2O) é um subproduto formado a partir da produção industrial de fertilizantes, no entanto esse material é considerado um passivo ambiental. Este estudo visa aplicar o fosfogesso, em sua forma hemidratada, em camadas finais de cobertura de aterros sanitários, em misturas com solo e aditivos bentoníticos. Para tal análise, as amostras foram submetidas a estudos de caracterização física e ensaios de permeabilidade para duas energias de compactação. Logo após foi executado uma simulação de variações sazonais por umedecimento e ressecamento para verificar possíveis interferências no comportamento hidromecânico. Também foi realizada uma estimativa matemática empírica para determinação da permeabilidade. Nesse estudo, a amostra com 6% de aditivo bentonítico compactada na energia Proctor Normal apresentou uma permeabilidade similar à amostra com 0% de aditivo bentonítico compactada na energia Proctor Intermediária e ambas dentro da faixa aceitável para aplicação em camadas de cobertura e barreira hidráulica. O solo também apresentou baixa permeabilidade em Proctor Intermediária, mas sofreu maiores alterações hidromecânicas durante os ciclos sazonais. A formulação empírica se mostrou aplicável a amostras lateríticas independentemente de sua variação na composição, mas quando a energia de compactação foi modificada a mesma equação não se aplicou, sendo necessário realizar outra adaptação matemática.ABSTRACT: The phosphogypsum (CaSO4.nH2O) is a by-product from the industrial production of fertilizers, however this material is considered an environmental passive. This study aims to apply the hemidrate phosphogypsum to final layers of landfill cover, in soil mixtures and bentonite additives. For this analysis, were carried out, in these materials, studies of physical characterization and permeability tests for two compaction energies. Afterwards a simulation of seasonal variations was performed through wetting and drying cycles to verify possible interferences in the hydro mechanical behavior of the materials. An empirical mathematical estimate was made to determine the permeability. In this study, the sample with 6% of bentonite additive in the Reduced Proctor Energy presented a permeability similar to the sample with 0% of bentonite additive compacted in the Standard Proctor Energy and both within the acceptable range for application in cover layers and hydraulic barrier. The soil also presented low permeability in the Standard Proctor, but underwent major hydromechanical changes during the seasonal cycles. The empirical formulation was applicable to lateritic samples regardless of their variation in composition, but when the compaction energy was modified the same equation was not applied and it is necessary to make another mathematical adaptation.

scholarly journals Deformation and Hydraulic Conductivity of Compacted Clay under Waste Differential Settlement

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 123 ◽  
Author(s):  
Sifa Xu ◽  
Cuifeng Li ◽  
Jizhuang Liu ◽  
Mengdan Bian ◽  
Weiwei Wei ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Deformation Behaviour ◽  
Differential Settlement ◽  
Laboratory Model ◽  
Compacted Clay ◽  
Geogrid Reinforcement ◽  
Cover System ◽  
Landfill Cover ◽  
Landfill Cover System ◽  
Land Reuse

Landfill is still the most important process to dispose of municipal solid waste in China, while landfill closure aims for pollution control, security control, and better land reuse. However, uneven settlement of landfill cover system is very likely to cause deformation and cracking. The objective of this paper is to examine the effects of geogrid reinforcement on the deformation behaviour and hydraulic conductivity of the bentonite-sand mixtures that are subjected to differential settlement. The laboratory model tests were performed on bentonite-sand mixtures with and without the inclusion of geogrid reinforcement. By maintaining the type and location of the geogrid within the liner systems as constant, the thickness of the bentonite-sand mixtures is varied. The performation of the liner systems with and without the inclusion of geogrid reinforcement was assessed by using jack to control differential settlement. Un-reinforced bentonite-sand mixtures of 100 mm and 200 mm thickness were observed to begin cracking at settlement levels of 2.5 mm and 7 mm, respectively. When settlement reached 25 and 42.5 mm, cracks for 100 mm and 200 mm thick bentonite-sand mixtures without geogrid penetrated completely. The settlement levels for bentonite-sand mixtures of 100 mm thickness with and without geogrid reinforcement was found to be 10 mm and 15 mm, respectively, when its hydraulic conductivity was around 5 * 10−7 cm/s. In comparison, geogrid reinforced bentonite-sand mixtures was found to sustain large deformation with an enhanced imperviousness. The results from the present study can provide theory evidence of predicting deformation and hydraulic conductivity of the landfill cover system.

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