• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.8-12
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• 2003

The centrifuge test result on capped sediment was compared to the advection- dispersion equation proposed for one layered to predict contaminant transport parameters. The fitted contaminant transport parameters for the centrifuge test results were one to three orders of magnitude greater than the estimated parameters from the advection-dispersion equation. This indicates that the centrifuge model over estimated the contaminant transport phenomena. Thus, the centrifuge provides a non-conservative approach to modeling contaminant transport. It should be also noted that the advection-dispersion equation used in this study is a one layered model. Two layered modeling approaches are more appropriate for modeling this data since there are two layers with different partitioning coefficients. Further research is required to model the centrifuge test using two-layered advection-dispersion models.

• 대한토목학회논문집
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• 제31권1C호
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• pp.1-10
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• 2011

본 논문에서는 제방 제체 하부지반에 투수계수 차이가 많이 나는 투수층(전석층)이 존재하는 김포제방에서 발생한 파이핑 현상을 모형실험 중 하나인 원심모형시험을 이용하여 모사하였다. 또한 원심모형실험과 동일 조건을 대상으로 수치해석을 수행하여 원심모형실험 결과와 비교하였다. 우선, 김포 제방을 바탕으로 원심모형실험을 수행할 단면을 결정하고, 간극수압계를 매설한 모형 제방에서 원심모형실험을 수행하였다. 실험을 통해 대부분의 물이 전석층으로 흐르는 것을 확인 하였으며 그로 인해 파이핑 현상이 발생하였다. 비디오 카메라 영상을 통해 기존의 연구 결과와 같이 전석층과 제내지 측 지표면과 거리가 가장 짧은 부분에서의 파이핑 현상을 확인하였다. 간극수압계를 통해 획득된 수압 분포 특성도 전석층으로의 물의 흐름으로 인해 파이핑 현상이 발생한 것임을 확인시켜주었다. 수치해석 결과 또한 원심모형실험 결과와 동일한 위치에서 파이핑 현상이 발생하는 것을 확인하였다. 원심모형시험을 통해 제방에서의 파이핑 현상을 모사하였으며 추후 제방 연구에서 원심모형시험을 이용하여 다양한 실험 및 현상을 평가, 예측 할 수 있을 것이라 판단된다.

• 산업기술연구
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• 제29권B호
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• pp.65-72
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• 2009

In this paper centrifuge model tests and numerical analysis on the coastal structure on the marine deposits of sand were performed to investigate the behavior of structure and foundation under the condition of wave action in field. In centrifuge model experiments, construction sequence of coastal structure such as preparation of sand deposit, excavation replacement, rubble mound with crushed stones and installment of coastal structure was reconstructed and the behavior of ground settlement during stage of construction was observed during tests. For the final stage of simulating the horizontal movement of coastal structure due to wave force, horizontal load was applied by horizontal loading apparatus being specially designed so that horizontal displacement of structure could be observed. Numerical analysis were also carried out and its results were compared with test results to assess the property of centrifuge mode experiments with respect to the behavior of structure as well as ground.

• 산업기술연구
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• 제31권A호
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• pp.79-86
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• 2011

This paper is results of centrifuge model experiment of investigating geotechnical engineering behavior of waterproof dike, located in soft grounds, in Saemankem in progress of construction. Centrifuge test with artificially increased gravitational level of 50g were performed to find ground settlements and excess pore-pressures developed during construction of waterproof dike by simulating the construction stages being predicted to occur in field so that the stability of waterproof dike could be assessed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 가을 학술발표회 논문집
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• pp.349-356
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• 1997

• 산업기술연구
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• 제31권B호
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• pp.81-90
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• 2011

Centrifuge modeling and numerical analysis on works of breakwater construction were performed to investigate the behavior of caisson type of breakwater and foundation treated with the method of DCM (Deep Cement Mixing) under the condition of wave action in field. In centrifuge modeling, construction sequence of breakwater caisson such as preparation of ground, treatment of DCM, installation of rubble mound, placement of breakwater caisson and lateral loading on the breakwater due to wave action were reconstructed. Lateral movement of model breakwater and ground reaction in the vertical direction were monitored during test. Stress concentration ratio between the untreated ground and the treated ground with DCM was evaluated from measurement of vertical stresses on each ground. Numerical analysis with the software of PLAXIS was carried to compare with Results of centrifuge model test. It was found that stability of model breakwater was maintained during stage of construction and the compared results about stress concentration ratio were in relatively good agreements.

• Geomechanics and Engineering
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• 제15권4호
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• pp.987-995
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• 2018

In this study, a relationship between small-strain shear modulus ($G_{max}$) and overconsolidation ratio (OCR) based on shear wave velocity ($V_S$) measurement was established to identify the stress history of centrifuge model ground. A centrifuge test was conducted in various centrifugal acceleration levels including loading and unloading sequences to cause various stress histories on centrifuge model ground. The $V_S$ and vertical effective stress were measured at each level of acceleration. Then, a sensitivity analysis was conducted using testing data to ensure the suitability of OCR function for the tested cohesionless soils and found that OCR can be estimated based on $V_S$ measurements irrespective of normally-consolidated or overconsolidated loading conditions. Finally, the developed $G_{max}$-OCR relationship was applied to centrifuge models constructed and tested under various induced stress-history conditions. Through a series of tests, it was concluded that the induced stress history on centrifuge model by compaction, g-level variation, and past overburden load can be analysed quantitatively, and it is convinced that the OCR evaluation technique will contribute to better interpret the centrifuge test results.

• 산업기술연구
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• 제27권A호
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• pp.111-120
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• 2007

This paper is results of experimental research on the effect of application of similarity related to permeability of soil on the consolidation behavior as centrifuge modeling of consolidation is performed with the centrifuge model facility. In this research, the permeability of soil was controlled by changing the viscosity of porewater as the mixed water with glycerin was used during the centrifuge model experiments. The effect of drainage path on consolidation was investigated by installing the vertical drains. A serise of centrifuge model tests with conditions of single vertical and radial horizontal drainage were carried out. Kaolinite and Jumunjin standard sand were used as soft clay and surcharges respectively during tests. For testing condition of single vertical drainage considering similarity of permeability, it was found that consolidation with mixed porewater with glycerin was delayed in comparisons sons with test results with water only. For conditions of horizontal drainage with vertical drains, a low permeability by changing the viscosity of pore water resulted in delayed degree of consolidation at an initial stage of consolidation. But, it predicted not much differences in settlement as long as the consolidation time was sufficiently long enough to finish consolidation. Consequently, it was found that similarity in permeability should be considered to be critical for the case of centrifuge model experiments related to consolidation with long drainage path.

• 한국지반공학회논문집
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• 제30권10호
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• pp.19-31
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• 2014

원심모형실험 중 지반모형의 상태 변화를 입체적으로 파악하기 위한 방법으로 전기비저항 탐사를 시도하였다. 탐사 시스템은 현장에서 널리 사용되는 검증된 상용 장비를 바탕으로 하였다. 컴퓨터 원격 조정으로 실험 시설 내에 설치된 탐사 장비를 통제하고 실시간 해석을 통해 결과 영상을 원심 모형실험 중에 바로 확인할 수 있도록 구성하였다. 구축된 탐사 시스템의 안정적 구동 여부를 점검하기 위해 불포화상태로 조성된 모형 지반 상단에 염수를 떨어뜨려 지반 내부로 이동하게 하고 전기비저항 탐사를 수행하였다. 10g로 원심력을 가한 상태에서 실험을 수행하고 시간대별 염수 침투상황을 전기비저항 영상으로 확인하였으며 일반 중력장에서 동일하게 실험한 결과와 비교하였다. 실험 종료 뒤 모형지반 수직 절단면을 이용하여 직접 측정한 전기비저항 값과 획득한 영상을 비교함으로써 신뢰성을 검증하였다.

• 한국철도학회논문집
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• 제7권2호
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• pp.149-154
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• 2004

Pile Bridge Abutments constructed on a soft base are affected by a lateral flow. Laterl flow pressure acting on Pile is very difficult to calculate because of, interation of ground and Pile. So, it is different to estimate displacement of Pile Bridge Abutments. This paper studied about possibility of the displacement estimation of Pile Bridge Abutments by using the equivalent sheet pile wall theory that was Randolph proposed in 1981. Analysis program through using the SAGE CRISP that is FEM program. Analysis data used Centrifuge test results of Springman(1991), Bransby(1997) and Ellis(1997)'s paper. In conclusion, maxium displacement that is carried out by centrifuge test and numerical analysis has occured at the head of pile, as well as Maximum displacement of pile is closely similar. But the moment acting on pile of numerical analysis is under estimated compare to the centrifuge test. Through the comparative study, it is found that displacement estimation by equivalent sheet pile wall is in relatively good agreement with the results of centrifuge test.