• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.1190-1197
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• 2009

Design parameters related to Yano's method(1984, 1985), one of experimental approaches having been used widely in Korea to estimate sedimentation and consolidation of dredged and reclaimed ground, were analyzed and their propriety were reassessed in this paper. Data analyses were performed on the basis of the settling test results using samples from the west coastal area of Korea. From analysis of results, for specific characteristics of these dredged and reclaimed marine soft clays, co-relations of initial water content - coefficient of sedimentation/ consolidation - initial setting velocity were evaluated. Relation between height of soil solid and surface height of slurry at the stages of initiation and termination of consolidation was also assessed. Finally ranges and average values of these design parameters were evaluated and typical empirical equations between these design parameters were also proposed.

• 한국경영과학회지
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• 제31권2호
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• pp.99-112
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• 2006

In our model, we keep inventory to satisfy uncertain demands which arrives irregularly. In this situation, we have additional two constraints. First, we need to have certain amount of order consolidation (consolidation constraint) for the orders to replenish the inventory because of production or purchase amount constraint. And also, if we order at a certain date which was set by administrative convenience, we have capacity constraint to order the consolidated order demands (capacity constraint). We show this variant inventory policy is needed in steel industry and note that there will be possible similar case in industry. To deal with this case, we invent a variant replenishment policy and show this policy is superior to other possible polices in the consolidation constraint case by extensive simulation. And we derive a combined solution method for dealing with the capacity constraints in addition to the consolidation constraints. For this, we suggest a combined solution method of integer programming and simulation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 2차
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• pp.3-12
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• 2010

Vertical drains have been commonly used to increase the rate of the consolidation of dredged material. The installation of vertical drains additionally provides a radial flow path in the dredged foundation. The objective of this study develops a numerical model for 2-D axisymmetric non-linear finite strain consolidation considering self-weight consolidation to predict the effect of vertical drain in dredged foundation which is in process of self-weight consolidation. The non-linear relationship between the void ratio and effective stress and permeability during consolidation are taken into account in the numerical model. The results of the numerical analysis are compared with that of the self-weight consolidation test in which an artificial vertical drain is installed. In addition, the numerical model developed in this paper is the simplified analytical method proposed by Ahn et, al (2010). The comparisons show that the developed numerical model can properly simulate the consolidation of the dredged material with the vertical drains installed.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.491-498
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• 2002

Dredged and reclaimed soft clays form slurry state which is very high water content and very low shear strength, experience large self-weight consolidation, nonlinear compressibility and permeability phenomenon would take place. In this case, a material functions which represent variety effective stress-void ratio-permeability relation (especially very low effective stress), are should be determined to predict nonlinear finite strain consolidation phenomenon forehand In this study, large slurry consolidometer with a 380mm diameter and a 1400mm height which is able to consolidation and permeability test, was developed to determine material function of very soft clay with a 500% initial water content clay, self-weight consolidation and low stress level consolidation (1Kpa, 3Kpa, 6Kpa, 12Kpa) was conducted and after each consolidation step permeability test also conducted. after final consolidation step, a constant rate of strain consolidation was conducted with undisturbed sample obtained from the large consolidometer. On the above result, material function was determined and laboratory test was modelled to evaluate its validity, numerical analysis on th field was compared to other method.

• 한국지반공학회지:지반
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• 제11권3호
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• pp.69-80
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• 1995

초기간극비가 큰 연약점토의 일차원 압밀특성을 조사하기 위하여 수치해석 연구슬 실시하였다. 유한변형률 압밀지배방정식을 바탕으로 양해차분의 수치해석기법을 사용하여 점토 토립자의 자중에 의한 압밀침하량의 산정을 실시하였다.

• 산업기술연구
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• 제20권A호
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• pp.93-100
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• 2000

This research is to investigate the self-weight consolidation settlement and desiccation shrinkage settlement of soft marine dredging clay by performing numerical and experimental works. Large column test were carried out investigate the consolidation settlement considering effect of the self-weight and desiccation shrinkage, and centrifuge model test was also carried out investigate self-weight consolidation settlement. Results of centrifuge model and large column experiments about changes of settlement with time were analyzed by using the numerical technique of explicit finite difference method considering effect of the self-weight and desiccation based on the finite strain consolidation theory. Centrifuge model test results were in relatively good agreements with analyzed results in terms of self-weight consolidation settlement with time. Large column test results showed quite different values from the numerically estimated one, carried by experimental conditions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.188-194
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• 2009

Consolidation settlement, a crucial parameter in geotechnical design of soft ground, has not been computed in a unique way due to different computation methods in practice. To improve computational error in calculating consolidation settlement, a number of researches has been attempted. Conventional 1-dimensional consolidation theory assumes the center of the clay layer as the representative point to obtain effective stress in calculation, which could resort to erroneous results. To calculate exact solutions considering initial distribution of effective stress, diving a stratum into multi-layers could resort to wasting time and effort. In the study, a novel methodology for calculating consolidation settlement via Guassian quadrature is developed. The method generally is capable of computing settlements in any case of the stress conditions encountered in fields.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.51-56
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• 2004

The sand compaction pile (SCP) method, which forms a composite ground by driving sand piles into clay deposit, is the most commonly used soil improvement techniques in many countries for more than 30 years. Installation of sand compaction piles reduces the amount of consolidation settlement and increases the bearing capacity of soft clay deposit. In this paper, field survey conducted to investigated the consolidation behavior of the composite ground improved by SCPs. It is suggested that the measured consolidation velocity is later than design theory, however measured consolidation settlement is higher than design theory.

• 한국해양공학회지
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• 제13권1호통권31호
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• pp.51-61
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• 1999

When a structure is built on the ground under consolidation, the instant corresponding contact pressure which the upper structure exerts on the ground is established. But, as the consolidation of the ground proceeds, the contact pressure is changed because of the flexural rigidity of the upper structure. This varied contact pressure exerts influence on the consolidation behavior of the ground. And, this varied consolidation behavior exerts on the contact pressure in retum. This kind of interaction between the upper struture and the olwer ground under consolidation contimues till all the consolidation process in finished. So this problem cannot be defined as a linear problem. In this paper an approximation method which can analyse this non-linear interaction problem is proposed by the FEM.

• 대한토목학회논문집
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• 제26권4C호
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• pp.247-254
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• 2006

온라인 실험 방법은 실험 정보를 직접 수치 해석에 사용하는 수치 실험법의 하나로, 지반의 역학적 특성이 요소 시험체로 부터 실시간으로 수치해석에 업데이트되므로 이상화된 역학모델을 사용하지 않고 지반 해석을 수행할 수 있다는 장점이 있다. 이 방법은 모래 지반을 주요한 대상으로 하는 지반내진공학 분야에서 주로 사용되어 왔으나 최근 압밀 문제에 적용할 수 있는 실험법이 개발되어 실내 검증과 현장검증이 시도되었다. 지금까지의 관련 연구에서는 압밀층 중앙에 요소 시험체를 위치시켜 평균적인 반응 거동만을 수치해석에 업데이트하는 방법이 주로 사용되어 왔으나, 이러한 경우에는 압밀층 두께가 두꺼워 질수록 해석 정도가 떨어질 수 있다는 점이 단점으로 지적되어 왔다, 따라서 압밀 문제에 대한 온라인 실험법의 유효성 및 가능한 해석 범위를 명확하게 하기 위해서는 이러한 영향요소를 완전히 배제할 수 있는 실험 조건을 적용하여 결과를 검토할 필요가 있다. 따라서, 본 연구에서는 동일한 조건 하에서 실시된 온라인 압밀 시험과 분할형 압밀시험 결과를 이용하여 점토 시료의 압밀 침하와 과잉간극수압 소산 재현 측면에서 온라인 압밀 실험 결과를 검토하였다. 실험결과, 온라인 압밀 실험은 재구성 카올리나이트 점토의 유효 응력에 따른 압축성 변화를 큰 모순 없이 재현해 내고 있었으며, 과잉간극수압 소산 속도 측면에서는 온라인 압밀 실험이 조금 빠른 것을 알 수 있었다. 이러한 실험 결과를 바탕으로 점토 시료의 과잉간극수압 소산 거동을 보다 정도 높게 예측하기 위해서는 점토의 투수성도 리얼타임으로 업데이트 할 수 있는 방향으로 실험 절차가 개선이 되어야 한다는 점과 과잉간극수압 소산 후의 변형에 대해서는 추가적인 연구나 개선이 필요하다는 점을 알 수 있었다.