• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1012-1023
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• 2008

This paper estimates the long-term settlement of In-cheon unsanitary solid waste landfills. which is 20 years old. The unsanitary solid waste landfills was subjected to pre-loading system over a period of 1 year, and the settlement for 300 landfill monitors provided measured data. This landfill contain relatively small amount of organic component, therefore the initial stage of settlement was very small. The existing settlement models are examineed to compare with the observed behavior of this site and, also to estimate long-term settlement. The Hyperbolic, Bjarngard & Edgers, and Power Creep Law models showed good agreement well with the measured settlement of the In-cheon unsanitary solid waste landfills.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.260-263
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• 2005

Uncontrolled landfills have been a threat to surrounding environment and human health. To examine the effect of hydrogeological properties on plume migration caused by landfill leachate, two representative landfills in Cheonan and Wonju were selected. In these landfills, seven and eight groundwater wells were installed respectively to monitor water quality and waterlevel, and to perform hydraulic and tracer tests. This study reports preliminary evaluation results including site characteristics, waterlevel measurement and slug tests.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1996.12a
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• pp.87-95
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• 1996

The stabilization and reclamation of old disposal sites is becoming more important as significant numbers of disposal sites are closed and abandoned. This technical paper covers an overview of the key issues and methodologies for stabilizing and constructing facilities on old landfills. The slide portion of this presentation also include photographs showing actual construction activities. The key issues that are prevalent in remediating and closing old landfills are : correcting the stormwater flow, leachate breakout, constructing cover caps, controlling landfill gas migration and odors, cleanup groundwater and stabilizing side slopes. Some key techniques for constructing facilities on old landfills include： use of piling, installation of active landfill gas systems, providing LFG barriers under buildings, using utilidors and flexible utility interfaces and designing for site settlement. This Paper provides proven conceptual methods for solving these problems.

• Coupled systems mechanics
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• v.3 no.1
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• pp.27-52
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• 2014

For landfill monitoring and aftercare, long-term prognoses of emission and deformation behaviour are required. Landfills may be considered as heterogeneous porous soil-like structures, in which flow and transport processes of gases and liquids interact with local material degradation and mechanical deformation of the solid skeleton. Therefore, in the framework of continuous porous media mechanics a model is developed that permits the investigation of coupled mechanical, hydraulical and biochemical processes in municipal solid waste landfills.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.432-435
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• 2006

To evaluate geology and extent of leachate migration around the landfills, electrical resistivity survey were conducted in area of uncontrolled landfills in Cheonan and Wonju. The Cheonan landfill is located above the paddy fields and the resistivity survey lines were crossed to confirm possible pollution of the paddy fields by leakage of the landfill leachate. In Wonju, the landfill and the downgradient paddy fields are divided by a concrete barrier wall. At the bottom of the landfill, there is a leachate settlement system but has not been in operation. And a total of 4 survey line installed (1 parallel and 3 perpendicular to mean groundwater flow direction). According to the resistivity survey results, the landfill leachate in Cheonan appeared to be restricted only within the interior of the landfill, not to migrate into the subsurface of the paddy fields. These results are well consistent with electrical conductivity values of groundwaters obtained from a periodic analysis of water qualities. In Wonju, however, it was inferred that the leachate emanating from the landfill migrated beneath the abandoned leachate settlement system and it would reach the downgradient paddy field.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.398-401
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• 2006

Two landfills of this study containing municipal wastes without any bottom liner and leachate treatment system have different landfill age, waste volume and most importantly different hydrogeologic settings. The one (Cheonan) is situated in an open flat area while the other (Wonju) is located in a valley. In the interior of the landfills, typical anaerobic conditions revealed by low DO and ${NO_3}^-$ concentrations, negative ORP values, high $NH_3$, alkalinity and $Cl^-$ concentrations were observed. Generally higher levels of contaminants were detected in the dry season while those were greatly lowered in the wet season. Significantly large decrease of Cl concentration in the wet season indicates that the dilution or mixing is one of dominant attenuation mechanisms of leachate. But detailed variation behaviors in the two landfills are largely different and they were most dependent on permeability of surface and subsurface layers. The intermediately permeable surface of 1.he landfills receives part of direct rainfall infiltration but most rainwater is lost to fast runoff. The practically impermeable surface of clayey silt (paddy field) at immediately adjacent to the Cheonan landfill boundary prevented direct rainwater infiltration and hence redox condition of the groundwaters were largely affected by that of the upper landfill and the less permeable materials beneath the paddy fields prohibited dispersion of the landfill leachate into downgradient area. In the Wonju landfill, there exist three different permeability divisions, the landfill region, the sandy open field and the paddy field. Roles of the landfill and paddy regions are very similar to those at the Cheonan. The very permeable sandy field receiving a large amount of rainwater infiltration plays a key role in controlling redox condition of the downgradient area and contaminant migration.

• Geotechnical Engineering
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• v.13 no.4
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• pp.5-12
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• 1997

The potentiality of water treatment sludge as the alternative liner and cover materials in landfills is investigated. A series of tests were performed on sludge admixtures to examine their compaction, compressive strength, leaching, hydraulic conductivity characterisit its and the compatibility with representative leachate within landfills. Results from the tests show that low hydraulic conductivity can berachieved with sufficient stabilizer contents and curing. It is recognized that the hydrauac conductivity decreases with increasing bentonite content and the percentage of bentonite needed to make the hydrauic conductivity below 1$\times$10-7cm/ sec was 40% for water treatment sludge. It was found that the effect of the municipal waste leachate on the hydraulic conductivity of the admixtures is negligible.

• Economic and Environmental Geology
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• v.28 no.5
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• pp.469-480
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• 1995

Gravity and magnetic surveys were carried out to investigate the three-dimensional configuration and characteristics of the landfills at Nanjido waste disposal site. For terrain correction and three-dimensional density inversion of gravity data an algorithm, which calculates the gravity effect of a three-dimensional body by using the solid angle method, is developed. This algorithm has been proved to give more accurate terrain correction values for the small survey area having varied topography like Nanjido site as compared with widely used methods such as Hammer's method and multiquadric equation method. Density inversion of gravity anomaly data gives very useful information about the lateral and vertical variation of the landfills, which can be used to discriminate the kinds of wastes. The average density of filled materials appears to be $1.7\;g/cm^3$ which is much higher than the value $(0.8\;g/cm^3)$ estimated by Seoul City. The lateral variation of density shows high correlation with the pattern of ongoing depression of the landfills. The northern region of the landfill no. 1, which shows low density and high depression, is closely associated with the industrial waste and sludge filled area. The magnetic anomaly data provide information about relative concentration of magnetic materials, which is also very useful to investigate characteristics of the fills. Several high positive anomaly regions on the reduced-to-pole magnetic anomaly map are appeared to be associated with the industrial waste fills, but certain industrial waste fills show low negative anomalies. This kind of magnetic information can be used in selecting drilling locations over landfills away from buried metal products during the stabilization process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.73-76
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• 2002

Biofilter performance to reduce C $H_4$ emissions from MSW landfills was tested under a variety of environmental and design conditions. The optimum soil moisture content for C $H_4$ oxidation in a loamy sand was 13% by weight. The addition of N $O_3$-N did not affect the C $H_4$ oxidation rate. Soil depths of 30cm and 60cm were equally efficient in C $H_4$ oxidation. When the C $H_4$ loading rate was decreased, the percentage of C $H_4$ oxidized increased. The maximum C $H_4$ oxidation rate was 27.2 mol $m^{-2}$ $d^{-1}$ under optimum conditions (loamy sand soil, 13% moisture content, 30cm soil depth, and an loading rate of 32.8 mol $m^{-2}$ $d^{-1}$). Based on the above results, the installation of a properly sized and managed biofilter above a landfill cover should be capable of achieving a major reduction in atmospheric methane emissions from MSW landfills built with RCRA covers.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.947-954
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• 2008

Waste landfills built on weak soils have the possibilities of the failure of slope and foundation due to the disposed waste loads. To ensure the landfill will sustain its stability within a limited site area, it's necessary to investigate and understand the characteristics of soft land by identifying the requirements for waste filling and by quantitative field measurement and management of landfills. In this paper, the stability analyses are performed using the field measurement data of Gimpo #2 Metropolitan Landfil. For the stability analysis, Tominaga-Hashimoto method and Kuriharh method, which may be able to manage the stability of the landfill quantitatively, are used.