• Earthquakes and Structures
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• 제17권5호
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• pp.521-532
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• 2019

This paper describes the construction of a laminar box for simulating the earthquake response of soil and structures. The confinement of soil in the transverse direction does not rely on the laminar frame but is instead achieved by two acrylic glass walls. These walls allow the behaviour of soil during an earthquake to be directly observed in future study. The laminar box was used to study the response of soil with structure-footing-soil interaction (SFSI). A single degree-of-freedom (SDOF) structure and a rigid structure, both free standing on the soil, were utilised. The total mass and footing size of the SDOF and rigid structures were the same. The results show that SFSI considering the SDOF structure can affect the soil surface movements and acceleration of the soil at different depths. The acceleration developed at the footing of the SDOF structure is also different from the surface acceleration of free-field soil.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권1호
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• pp.66-72
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• 2010

The partitioning tracer method is to estimate the residual saturation of nonaqueous phase liquid (NAPL) in soils by analyzing tracer's retardation induced by the reversible partitioning of tracer with NAPL. This study is to estimate the residual diesel saturation in soils using the partitioning tracer method. Two-dimensional soil box was used to represent the 2-dimensional flows of groundwater and tracer solution in the saturated aquifer, and the soil box was filled with soil and then saturated with water. The residual diesel saturation was induced in saturated soil, and the partitioning tracer method was applied. The results from batch-partitioning experiment indicated that the diesel-water partitioning was linear with respect to tracer's concentration, and the partition coefficient of tracer between diesel and water was measured by their linearities. The groundwater flow in the saturated aquifer was simulated in the 2-dimensional soil box, and the residual diesel contamination was visually identified. The results from the partitioning tracer method with or without diesel in soils confirmed that 4-methyl-2-pentanol, 2-ethyl-1-butanol and 1-hexanol, can be used as a detecting method for diesel contamination. By the accuracies of estimations for diesel contamination using the partitioning tracer method, 2-ethyl-1- butanol showed the highest accuracy with 83%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.974-981
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• 2005

Because general laboratory tests for sand compaction pile method including unit-cell test device have fixed outside diameter, as area replacement ratio increase, diameter of sand pile increase. These condition can bring about overestimation of stiffness of composite ground. In addition, existing large soil box which consist of bellows type loading plate can occur serious mistake in checking the amount of drained water because there are additional drainage along the inside wall in device. Overcoming these shortcoming, this paper developed modified large scale soil box consist of piston type load plate. In this study, using this device, series of modified large scale soil box tests were performed, and investigated the settlement and stress transportation characteristics with area replacement ratio in sand compaction pile method.

• 한국지반신소재학회논문집
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• 제22권4호
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• pp.83-92
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• 2023

In this study, we conducted verification of key influencing factors during cone penetration testing using the developed Mini Cone Penetration Tester (Mini-CPT), and compared the experimental results with empirical formulas to validate the equipment. The Mini-CPT was designed to measure cone penetration resistance through a Strain Gauge, and the resistance values were calibrated using a Load Cell. Moreover, the influencing factors were verified using a model ground constituted in a soil box. The primary influencing factors examined were the boundary effect of the soil box, the distance between cone penetration points, and the cone penetration speed. For the verification of these factors, the experiment was conducted with the model ground having a relative density of 63.76% in the soil box. It was observed that the sidewall effect was considerably significant, and the cone penetration resistance measured at subsequent penetration points was higher due to the influence between penetration points. However, within the speed range considered, the effect of penetration speed was almost negligible. The measured cone penetration resistance was compared with predicted values obtained from literature research, and the results were found to be similar. It is anticipated that using the developed Mini-CPT for constructing model grounds in the laboratory will lead to more accurate geotechnical property data.

• 한국건설관리학회논문집
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• 제10권6호
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• pp.40-47
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• 2009

경량기포혼합토는 경량성으로 인해 구조물 등에 작용하는 하중이 저감되어 연약지반의 뒷채움 재료로 사용되지만, 일반토사에 비하여 초기시공비용이 많이 소요되어 아직 국내에서는 많이 적용되고 있지 않다. 주로 뒷채움 재료는 초기시공비가 적게 소요되는 일반토사를 사용하고 있으나, 일반토사의 덧씌우기 공법은 횟수가 증가함에 따라 사용연수가 감소된다. 특히 연약지반에 설치된 BOX구조물이나 교대 뒷채움 인근의 단차 발생 시 덧씌우기 공법은 일시적인 대체공법은 가능하지만, 덧씌우기 두께에 대한 하중만큼 추가 하중이 발생하게 되므로 결국 단차에 대한 해결책은 되지 못한다. 따라서 본 연구에서는 BOX구조물 뒷채움 재료인 일반토사와 경량기포혼합토의 두 가지 대안에 대하여 LCC 분석을 실시하고 경제적 측면에서 보다 합리적인 의사결정을 할 수 있는 경제성 분석을 제시하고자 하였다. 그 결과 경량기포혼합토가 일반토사에 비해 초기시공비용은 많이 소요되지만 유지관리 측면에서는 비용이 더 적게 소요되어 경제성을 확보할 수 있는 것으로 분석되었다.

• 한국구조물진단유지관리공학회 논문집
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• 제6권3호
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• pp.91-96
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• 2002

There are many methods for analyzing underground box structures. One is the method of Iterative removal of tensional spring. The other is the method of modeling of ground to 8-node elastic-plastic planar element. In this study, We use inelastic soil spring element for analyzing underground box structures. First, if N-value is over 50, the results of inelastic soil spring method is the same as the method of 8-node planar element in last stage. Second, as N is increasing, element forces in two methods are generally decreasing. Third, as N-value is increasing, element forces in two method are generally decreasing and displacement has decreasing incline. This is the same as the force-displacement curve of general underground structures.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.412-419
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• 2011

With an increase in rail traffic, developing activities around structures of railway have been expanded. Inevitably, the changes to cross though sub-structures of railway have been getting increased. However, this situation affects on the safe operation of trains. Generated wheel load makes on the result in settlement on roadbed and damages on track materials. Therefore, via the numerical analysis were carried out for the box structure and subground using FEM analysis program called. Visual FEA/Geo 4.19. Parametric studies were performed by changing soil depth above box structure constructed in railway embankment. A standard live load was applied to simulate loads from train. Through this study, a minimum required soil depth above subground box structure was recommended based on deformation and stresses in concrete railway system.

• 한국도로학회논문집
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• 제15권5호
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• pp.47-55
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• 2013

PURPOSES : The purpose of this study is to investigate the optimal joint positions which can minimize distresses of concrete pavement containing box culvert with horizontally skewed angles. METHODS : The concrete pavement containing the box culvert with different skewed angles and soil cover depths was modeled by 3 dimensional finite element method. The contact boundary condition was used between concrete and soil structures in addition to the nonlinear material property of soil in the finite element model. A dynamic analysis was performed by applying the self weight of pavement, negative temperature gradient of slab, and moving vehicle load simultaneously. RESULTS : In case of zero skewed angle ($0^{\circ}$), the maximum tensile stress of slab was the lowest when the joint was positioned directly over side of box culvert. In case there was a skewed angle, the maximum tensile stress of slab was the lowest when the joint passed the intersection between side of the box culvert and longitudinal centerline of slab. The magnitude of the maximum tensile stress converged to a constant value regardless the joint position from 3m of soil cover depth at all of the horizontally skewed angles. CONCLUSIONS : More reasonable and accurate design of the concrete pavement containing the box culvert can be possible based on the research results.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.855-858
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• 2008

경량기포혼합토는 경량성으로 인해 구조물등에 작용하는 하중이 저감되어 연약지반의 뒷채움 재료로 사용되지만, 일반토사에 비하여 초기시공비용이 많이 소요되어 아직 국내에서는 적용하고 있지 않다. 주로 뒷채움 재료는 초기시공미가 적게 소요되는 일반토사를 사용하고 있으나, 일반토사의 덧씌우기 공법은 횟수가 증가함에 따라 사용연수가 감소된다. 특히 연약지반에 설치된 BOX구조물이나 교대 뒷채움 인근의 단차 발생 시 덧씌우기 공법은 일시적인 대체공법은 가능하지만, 덧씌우기 두께에 대한 하중만큼 추가 하중이 발생하게 되므로 결국 단차에 대한 해결책은 되지 못한다. 따라서 본 연구에서는 BOX구조물 뒷채움 재료인 일반토사와 경량기포혼합토의 두 가지 대안에 대하여 LCC 분석을 실시하며, 경제적 측면에서 보다 합리적인 의사결정을 할 수 있는 경제성 분석을 제시하고자 하였다. 그 결과 경량기포혼합토가 일반토사에 비해 초기시공비용은 많이 소요되지만 유지관리 측면에서는 비용이 더 적게 소요되어, 6년 이내에 경제성을 확보할 수 있는 것으로 분석되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
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• pp.105-116
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• 1999

The Inchon International Airport site was formed by reclaimed soil from the sea. The average thickness of soft soil Is about 5 m and most of soft soils are normally consolidated or slightly over consolidated. There are many box culverts which are being constructed under the runways in the airfield. Sometimes, differential settlement can be occurred in the adjacent of box culvert or underground structures at the top layer of runway Soil compaction at very near to the structure is not easy all the time. Thus, one layer of geogrid was placed at the bottom of lean concrete layer for the concrete paved runway and at the middle of cement stabilized sub-base course layer for the asphalt paved runway. The length of geogrid reinforcement is 5m from the end of box culvert for both sides. The extended length of geogrid was 2m from the end of backfill soil in the box culvert. The tensile strength tests of geogrid were conducted for make sure the chemical compatibility with cement treated sub-base material. The location of geogrid placement for the concrete paved runway was evaluated. The construction damage to the geogrid could be occurred. Because the cement treated sub-base layer or lean concrete was spread by the finisher. The magnitude of tensile strength reduction was 1.16%~1.90% due to the construction damage and the ultimate tensile strength is maintained with the specification required. Total area of geogrid placement in this project is about 50,000 $m^2$.