Performances of Landfill Liners Under Optimum Moisture Conditions (original) (raw)
2008, Electronic Journal of …
This paper addresses the study conducted on the performance of landfill liner interface parameters. Interface shear strength parameters for various combinations of 12 different lining materials were studied and presented in this paper. This comprehensive testing program covers the interfaces between: 1) soil and compacted clay liner (CCL), 2) geomembrane (HDPEs or PVC) and soil, 3) geosynthetic clay liner (GCL) / CCL and soil, 4) geomembrane and geotextile, 5) geotextile and soil, 6) geotextile and GCL / CCL, and 7) geomembrane and GCL / CCL. The experiments were conducted under optimum moisture condition. Tabulated summaries of interface test results under optimum moisture condition are presented in the paper.
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Performances of Landfill Liners under Dry and Wet Conditions
Geotechnical and Geological Engineering, 2011
This paper addresses the study conducted on the performance of landfill liner interface parameters. Interface shear strength parameters for various combinations of 9 different lining materials were studied and presented in this paper. This comprehensive testing program covers the interfaces between:
Large-Scale Shear Tests on Interface Shear Performance of Landfill Liner Systems
Geosynthetics in Civil and Environmental Engineering
Interface shear performance of various landfill liner systems were evaluated for landfill stability by conducting large scale shear tests. Testing program covers the interfaces between (1) geosynthetics (geomembrane (GM) sheet (HDPE and PVC) and non-woven geotextile) and subsoil, (2) geosynthetics and compacted clay liner (CCL), and (3) GM and geotextile. The focus of this paper is placed on interface shear performance under both as installed condition (dry for geosynthetics and optimum moisture content for CCL or subsoil) and saturated / wet condition, since landfill liner system is often subjected to saturated / wet condition due to the higher water retention capacity of CCL as well as the contact to leachate and/or groundwater. For geotextile-GM interface, there is no significant effect on the interface shear strength. The saturated CCL-GM interface had lower shear strength compared to the interface under as installed condition, although the shear performances of CCL-geotextile interface under both conditions are similar to each other. For the interfaces between geosynthetics and subsoil, the frictional resistance of HDPE with textures surface had a significant drop from 23 to 15 degree in the saturated / wet condition.
Influence of Surface Texture on the Interface Shear Capacity of Landfill Liner
Geomembrane is one of the most widely used geosynthetics in various civil engineering applications. Its primary function is to act as a barrier for liquid and/or vapour. Smooth geomembrane is frequently used in combination with different soils, and however due to its low surface roughness, the main concern in the design is to ensure adequate shear capacity along the smooth geomembrane/soil interface. The use of smooth geomembrane will lead to low interface shear capacity between landfill liner components which can be considered as one of the major factors in the landfill slope stability failures. Modification of HDPE geomembrane from smooth surface to textured surface is therefore required to improve interface shear capacity of landfill liners. In this study, several interfaces of landfill liner components were tested by using large scale shear box. The combinations used were (1) Sand:Bentonite (100:5)/Smooth HDPE; (2) Sand:Bentonite (100:10)/Smooth HDPE; (3) Sand:Bentonite (100:5)/...
Laboratory Studies on Unconfined Compressive Strength of Solid Waste Landfill Liner Material
Compacted natural clay soils are used as liners and covers in waste containment facilities. Liners are generally made of compacted natural inorganic clays or clay soils. The liner is one of the most important elements on a waste disposal landfill. Clay soils are used for constructing landfill liners because they have low hydraulic conductivity and can attenuate organic and inorganic contaminants. In the absence of impermeable natural soils, compacted mixtures of bentonite and soil are used to form barriers to fluid transmission. The shear strength and unconfined compressive strength may have influence over the hydraulic barrier which is the indicator of the performance of the liner. Laboratory tests are conducted on clay soil samples mixed with microsilica in different proportions to demonstrate to demonstrate the increase in the strength of compacted clay soil liners and covers. The strength behavior observed in this study of clay is used to evaluate the performance of clay soil with and without mircosilica admixture addition.
Landfill Liners Stability Assessment using Interface Parameters
Landfill liner stability assessment using interface shear strength parameters have been a tedious testing and analysis process. The current testing procedures are based on ASTM testing guideline and basic fundamental engineering testing philosophies. Hence there is need for much ideal testing equipment which can perform the entire test series required for landfill liner parameter evaluations. The equipment are required to perform interface test between 1) soil and soil (CCLs), 2) geomembrane (HDPEs and PVC) and soil, 3) geosynthetic (GCLs) / compacted clay liners (CCLs) and soil, 4) geomembrane and geotextile, 5) geotextile and soil, 6) geotextile and geosynthetic (GCLs) / compacted clay liners (CCLs), 7) geomembrane and geosynthetic (GCLs) / compacted clay liners (CCLs). Having such high requirement and testing complexity for landfill liner system, this paper addresses the modification adopted to a large scale shear box in order to perform the above said interface tests. The modified large scale shear box was used to study interface performance of various combination of liners. Test data were compiled into a landfill model to study the stability performance of landfill liners under static and seismic loading to identify suitable liner configuration for both single and composite liner systems. The data from analysis results are compiled as quick reference guide for engineers involved in landfill liner design and maintenance. Details of laboratory test data and analysis results will be presented herewith. 4 TESTING APPARATUS Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.25 Case 2E-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.20 Case 2D-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.15 Case 2C-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.10 Case 2B-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.00 Case 2A-3 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.25 Case 2E-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.20 Case 2D-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.15 Case 2C-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.10 Case 2B-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.00 Case 2A-2 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.25 Case 2E-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.20 Case 2D-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.15 Case 2C-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.10 Case 2B-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.00 Case 2A-1 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.25 Case 1E-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.20 Case 1D-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.15 Case 1C-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.10 Case 1B-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.00 Case 1A-3 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.25 Case 1E-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.20 Case 1D-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.15 Case 1C-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.10 Case 1B-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.00 Case 1A-2 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.25 Case 1E-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.20 Case 1D-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.15 Case 1C-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.10 Case 1B-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.00 Case 1A-1 DESCRIPTION CASES Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.25 Case 2E-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.20 Case 2D-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.15 Case 2C-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.10 Case 2B-3 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.00 Case 2A-3 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.25 Case 2E-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.20 Case 2D-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.15 Case 2C-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.10 Case 2B-2 Slope height of 10m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.00 Case 2A-2 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.25 Case 2E-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.20 Case 2D-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.15 Case 2C-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.10 Case 2B-1 Slope height of 10m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.00 Case 2A-1 Slope height of 10m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.25 Case 1E-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.20 Case 1D-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.15 Case 1C-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.10 Case 1B-3 Slope height of 30m with 135m length with back slope angle of 1H:1V and seismic coefficient of 0.00 Case 1A-3 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.25 Case 1E-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.20 Case 1D-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.15 Case 1C-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.10 Case 1B-2 Slope height of 30m with 135m length with back slope angle of 2H:1V and seismic coefficient of 0.00 Case 1A-2 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.25 Case 1E-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.20 Case 1D-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.15 Case 1C-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.10 Case 1B-1 Slope height of 30m with 135m length with back slope angle of 3H:1V and seismic coefficient of 0.00 Case 1A-1 DESCRIPTION CASES
Effect of Compaction on Soil Physical Properties of Differently Textured Landfill Liner Materials
Geosciences, 2018
Mineral landfill liners require legally-fixed standards including a sufficiently-high available water capacity (AWC) and relatively low saturated hydraulic conductivity values (Ks). For testing locally available and potentially suitable materials with respect to these requirements, the soil hydraulic properties of boulder marl (bm) and marsh clay (mc) were investigated considering a defined compaction according to Proctor densities. Both materials were pre-compacted in 20 soil cores (100 cm3) each on the basis of the Proctor test results at five degrees of compaction (bm1–bm5; mc1–mc5) ranging between 1.67–2.07 g/cm3 for bm and 1.09–1.34 g/cm3 for mc. Additionally, unimodal and bimodal models were used to fit the soil water retention curve near saturation and changes in the pore size distribution (PSD). The structural peak of the PSD in the fraction of pore volume between −30 and −60 hPa was more pronounced on the dry side (bm1–2, mc1–2) than on the wet side of the Proctor curve (bm...
E3S Web of Conferences
The design of a competent basal lining system is crucial in ensuring a long-lasting and functional engineered municipal solid waste (MSW) landfill. However, due to the inclusion of numerous geosynthetics and geomaterials forming a multi-layered lining system, there rises an uncertainty on determining the critical or weakest interface. This is exacerbated by the different properties offered by these lining materials and their inter-crossing functions in landfills. According to ASTM D5321-20 standard, the interface shear strengths used in design of bases and side-slopes of lining systems are determined through a single interface testing configuration. However, minimal research has been done to evaluate the consequences of multi-interface testing configurations on the minimum factors of safety (FoSmin). The present study was thus conducted to further investigate this phenomena while establishing the appropriateness of double interface testing configuration using large direct shear equi...
International Journal of Geosynthetics and Ground Engineering
Geosynthetics form an integral part of engineered municipal solid waste (MSW) landfill lining systems, as they provide cost saving and technical benefits. Their introduction in lining systems, however, has presented new potential interfaces for shear failure especially on bases and on side slopes of engineered MSW landfills. In the laboratory, interface shear strength parameters used in slope designs of landfill lining systems are determined through single-interface testing configurations as per ASTM D5321-20 and D6243-20 standards. However, single-interface testing configurations do not provide a clear understanding of shear strength transfers among the lining components and does not aid in pin-pointing the interface facilitating failure especially when a multi-layered lining system has been proposed. Multi-interface testing configurations present an alternative that may address such limitations. But there is minimum information available on this type of testing as it is not stipul...
Evaluation of a four-component composite landfill liner system
Environmental Geotechnics, 2015
The performance of four different municipal solid waste landfill liner systems common in the United States, that is, USEPA Subtitle D prescribed composite liner system, composite liner system consisting of a geomembrane (GM) overlying a geosynthetic clay liner (GCL), Wisconsin NR500 liner system, and a proposed four-component composite liner system that is a combination of the GCL composite liner and Subtitle D liner system (with a 61-cm or 91•5-cm thick low hydraulic conductivity compacted soil), were evaluated in terms of leakage rate, solute mass flux, and cumulative solute mass transport. Leakage rates through circular and non-circular GM defects were analysed using both analytical and numerical methods. For the mass flux evaluation, solute transport analyses using GM defects and diffusion of volatile organic compounds through intact liners were conducted using one-and three-dimensional numerical models. Cadmium and toluene were used as typical inorganic and organic substances, respectively, in the analyses. The y lateral orthogonal direction z vertical direction or depth from top of liner z m normalised coordinate in z-direction in geomembrane l rate of constant of first-order rate reaction r b bulk density of compacted soil liner t a apparent tortuosity Environmental Geotechnics Volume 4 Issue EG4
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