• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.77-80
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• 2001

The element-free Galerkin (EFG) method is one of meshless methods, which is an efficient method of modeling problems of fluid or solid mechanics with complex boundary shapes and large changes in boundary conditions. This paper discusses the theory of the EFG method and its applications to modeling of groundwater flow. In the EFG method, shape functions are constructed based on the moving least square (MLS) approximation, which requires only set of nodes. The EFG method can eliminate time-consuming mesh generation procedure with irregular shaped boundaries because it does not require any elements. The coupled EFG-FEM technique was introduced to treat Dirichlet boundary conditions. A computer code EFGG was developed and tested for the problems of steady-state and transient groundwater flow in homogeneous or heterogeneous aquifers. The accuracy of solutions by the EFG method was similar to that by the FEM. The EFG method has the advantages in convenient node generation and flexible boundary condition implementation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 사용종료 매립지의 안정화 에 관한 국제 세미나
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• pp.97-101
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• 1996

Municipal and sanitary landfills can pose environmental problems due to leachate, landfill gas md unstable geotechnical properties. Most governmental bodies delay the correction of landfill problems or landfill replacement until a crises stage is reached. The replacement of a landfill is often made difficult due to costly regulatory controls, public opposition to siting and the high cost of closure for the previous landfill unit. Solutions to extending landfill life and capacity Involve waste minimization by recycling, refuse compaction and waste-to-energy incineration. Incineration can reduce the volume of refuse by 50-95%. The largest installed bases of municipal waste Incinerators are located in Japan and the U.S. The volume of waste contained in a landfill can be estimated by load count tabulations, weight-and-volume measurements or a material balance analysis based on the trash profile of user categories. for an existing landfill, core samples may be collected and analyzed for use in a material balance analysis. Newly generated refuse contains approximately 50% of the heating value of coal. However, landfill properties vary significantly due to the waste profile of the contributors and biodegradation due to time and weathering. The volume of the Nanji-do landfill

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.352-355
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• 2003

27 passive systems in 21 mines constructed by The Coal Industry Promotion Board since 1996 were investigated to evaluate the treatment efficiency of systems and find problems in each system, which will eventually lead to the improvement or suggesting the alternative method of the passive treatment system. Problems in operation include overflow, leakage, inefficiency and unusablness. The efficiency of systems which has been evaluated by metal(Fe) removal rate and/or by acidity removal rate do not reflect the poor removal rate of S $O_4$$^{2-}$. Especially high concentration of S $O_4$$^{2-}$ and high COD in the beginning of the operation would decrease the bacteria activity due to the lack of the nutrition. To solve the problem of overflow the upflow-type SAPS is being considered.

• 한국농공학회지
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• 제40권6호
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• pp.95-103
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• 1998

Solutions of geotechnical engineering problems require calculation of deformation and stresses during various stages of loading. Powerful numerical methods are available to make such calculation even for complicated problems. To get accurate results, realistic stress-strain relationships of soil are dependent on a number of factors such as soil type, density, stress level and stress path. Attempts are continuously being made to develope analytical models for soils incorporating all such factors. The nature of stress-path dependency, the principle that governs deformations in sand, and the use of Lade's single work-hardening model for predicting sand response for a variety of stress-paths have been investigated and are examined. The test results and the analyses presented show that under some conditions sand exhibits stress-path dependent behavior. The strains calculated from Lade's single work-hardening model are in reasonable agreement with those measured, but some discrepancies occur. The largest difference between measured and calculated strains occurs for proportional loading with increasing stresses and for stress-path directions.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권6호
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• pp.1-7
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• 2013

Groundwater development and use have been increasing in Korea causing frequent occurrences of related hazards such as groundwater level decline, land subsidence, and groundwater contamination. To tackle these groundwater problems, central and local governments have set-up and maintained many groundwater monitoring programs such as the National Groundwater Monitoring Network and the Groundwater Quality Monitoring Network, which collect very valuable data on the overall status of domestic groundwater to aid proper groundwater management. However, several problems mainly related to the remediation of contaminated groundwater remain unresolved. Recently, there have been some incidents related to the contamination of groundwater, and these have drawn the concern of the Korean people. Although groundwater contamination has been investigated in detail, actual groundwater remediation work has not yet been implemented. The remediation of the contaminated groundwater must begin immediately in order to sustain the eco-system service of clean groundwater and enhance the welfare of the Korean people.

• 기술사
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• 제41권3호
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• pp.35-39
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• 2008

The most common soil contaminants are petroleum-based. Hydrocarbons from diesel fuel and gasoline are widespread problems, as are total petroleum hydrocarbon(TPH). There are two distinct classes of soil remediation: in-situ, or on-site, and ex-situ, or off- site. On-site cleanups are often preferred because they are cheaper. On the other hand, excavating a contaminated area and transporting it to a remote site before cleaning it can often be more complete. Ex-situ remediation also has the added bonus of taking the bulk of contaminants off-site before they can spread further. In addition, in-situ situations are limited because only the topside of the soil is accessible.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.135-142
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• 2000

A framework alternative to that of classical slope stability analysis is developed, wherein the soil mass is treated as a continuum and in situ soil stresses and strengths are computed accurately using inelastic finite element methods with general constitutive models. Within this framework, two alternative methods of stability analysis are presented. In the first, the strength characteristics of the soil mass are held constant, and the gravitational loading on the slope system is increased until failure is initiated by well-defined mechanisms. In the second approach, the gravity loading on the slope system is held constant, while the strength parameters of the slope mass are gradually decreased until well-defined failure mechanisms developed. Details on the applying both of the proposed methods, and comparisons of their characteristics on a number of solved example problems are presented.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.390-393
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• 2002

Many researchers have studied for the barrier liner in the landfill that is mixed with clay mineral, native soils and solidified agent. However, they have a littel but problems for safety construction and maintenance as a bottom liner systems in the landfill. In this paper the authors studied the effects on hydraulic conductivity by electric-chemical ion-exchange agent that is a soil stabilization agent(Sulphonated Oil), The application of the soil stabilization agent to meet the hydraulic conductivity of clay liner in landfill is possible if the additive quantity and a proper reaction time is determined relevantly in the laboratory test.

• 물과 미래
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• 제6권1호
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• pp.13-18
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• 1973

If the temperature of free water drops below the freezing point the water turns into ice and its volume increases. Analyzing of the results in test, it is hoped that these is broadly used in engineering plan. The compressive strength of frozen soils and the unconfined compressive strength of the ice. The creep strength depends on factors including creep ratio, time, strain and temperature. For a linear decreases in temperature, strength predicts an exponential increasing. The relationships between dry unit weight and compressive strength, water content and freezing with compacted soil samples, have been analyzed to understand the strength of frozen soil. Therefore, it is thankful that the results of analsis shall find useful application as a framework for generalizing experimental information as well as a basis for solving various frozen soil mechanics problems.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.324-327
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• 2006

The high Fe and Mn contents in riverbank filtered groundwater often provoke problems on the water quality, We analyzed the mineral and chemical compositions of the soil samples taken from the different depths of the fluvial deposits at various locations in the riverbank filtration area, Daesan-Myeon. The groundwater chemistry data were also collected from the equivalent depths with the soil samples at the boreholes in July and December, 2005. The relationships between the enrichment characteristics of Fe and Mn in the groundwater and the mineralogical and physicochemical properties of the fluvial deposits were carefully analyzed. The results indicate that the Fe and Mn contents in the groundwater vary with seasonally and show different enrichment behaviors.