• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.231-238
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• 2000

Sand piling method is one of the most widely used methods to improve soft soils. There are several methods to install sand piles, but driven pile method is considered as one of the easiest method. This method simply pushes down the sand piles into soft soils, so that the excess pore pressure would be generated if the soil is saturated. This pore pressure acts as consolidation load. If the amount of sand pile induced pore pressure can be predicted in reasonable ways, the effects of sand piling to improve soft soils would be predicted, and the height of preload can be reduced. In this article, sand pile induced excess pressure was predicted by cavity expansion theory, and the predicted values were compared with the field measured values. The results showed fair agreements between the measured and the predicted excess pore pressure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.399-404
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• 2008

The influence of gas hydrate dissociation on submarine slope stability was studied in this paper. Gas hydrates are stable under high pressure and low temperature conditions. Once gas hydrate dissociates due to natural or human activities, it generates large amount of gas and water. During gas hydrate dissociation, a pore pressure between soil particles increases and results in the loss of an effective stress and degradation of soil stiffness. A pore pressures model was proposed to calculated excess pore pressures generated by gas hydrate dissociation at the Storegga Slide. A slope stability analysis for the Storegga Slide using a two dimensional finite difference method was carried out by considering excess pore pressures due to gas hydrate dissociation. Since the excess pore pressure calculated by the proposed method resulted in the considerable loss of stiffness and strength in slope, a submarine slope failure occurred at the Storegga slide was well simulated.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.201-208
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• 2000

In this study, the behavior of saturated sandy soils under dynamic loads - pore water pressure and effective stress - was investigated using Disturbed State Concept(DSC) model. The model parameters are evaluated from laboratory test data. During the process of loading and reverse loading, DSC model is utilized to trace strain-hardening and cyclic softening behavior. The procedure of back prediction proposed in this study are verified by comparing with laboratory test results. From the back prediction of pore water pressure and effective mean pressure under cyclic loading, excess pore water pressure increases up to initial effective confining pressure and effective mean pressure decrease close to zero in good greement with laboratory test results. Those results represent the liquefaction of saturated sandy soils under dynamic loads. The number of cycles at initial liquefaction using the model prediction is in good agreement with laboratory test results. Therefore, the results of this study state that the liquefaction of saturated sandy soils can be explained by the effective tress analysis.

• 한국항해항만학회지
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• 제37권2호
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• pp.173-179
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• 2013

파랑과 해저지반 그리고 해안 해양 구조물과의 상호작용은 지반공학뿐만 아니라 해안공학 분야에서도 중요한 이슈중의 하나이며, 파랑에 의해 해저지반 내부에 발생하는 응력 및 간극수압 거동의 파악은 다양한 해안 해양 구조물의 기초 설계 및 해저 연안 지반의 불안정성 검토에 있어서 중요한 과제이다. 해저지반의 불안정에 대한 문제 중, 파랑에 의한 해저지반의 액상화는 기존의 연구를 통하여, 두개의 메커니즘이 존재한다는 것이 밝혀졌으며, 이는 각각 파랑에 의해 해저지반 내부에 발생하는 과잉간극수압의 변동 특성 및 잔류 특성에 따른 것이다. 본 연구에서는 일본 시코쿠 코치(高知)현에 위치하고 있는 코치항에서 채취한 토사에 대한 동적 특성을 고려하여, 파랑에 의해 해저지반 내부에 발생하는 침투류에 의한 잔류과잉간극수압에 대하여 해석을 하였으며, 더 나아가, 코치항에서 계측된 값과 비교 분석을 하였다.

• 한국지반공학회논문집
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• 제27권12호
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• pp.27-37
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• 2011

강한 지진 발생 시 뒤채움내의 과잉간극수압의 증가에 의해 지반이 액상화 되었을 때, 주변의 액상화 지반보다 작은 단위중량을 가진 지중 매설구조물은 부상하는 현상이 발생한다. 뒤채움에서의 과잉간극수압의 증가와 지중 매설 구조물 부상량의 관계를 설명하기 위해 동적 원심모형 실험을 수행되었다. 본 연구에서는, 매설구조물의 부상현상에 영향을 미치는 요인으로써 직접요인과 간접요인이 실험에 고려되었다. 이러한 요인들 중에, 과잉간극수압비의 증가에 영향을 주는 중요한 요인은 직접요인으로써의 지하수위, 뒤채움의 상대밀도, 그리고 입력 지진가속도의 크기이다. 그리고 이 요인들은 지중 매설구조물의 부상량에도 크게 영향을 주는 것으로 나타났다.

• 한국농공학회논문집
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• 제54권1호
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• pp.39-45
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• 2012

In this study, field test on utilization of recycled aggregates and crushed stone as horizontal drains to use an alternative material of sand in soft ground is practiced. The settlement with time showed similarly ranged from 28.4-30.3 cm in the all horizontal materials. The excess pore water pressure of the recycled aggregates and crushed stone showed smaller than sand. The small the excess pore water pressure becomes faster the consolidation period and it can reduces the amount of residual settlement. Therefore, it was verified as having enough to an alternative materials that the field applicability is excellent. The distribution of earth pressure with time showed similarly in the all horizontal materials. The recycled aggregates and crushed stone was very applicable to practice because there is no mat resistance in the horizontal drains layer. The penetration rate in the SCP and PVD improvement sections did not show large differences as the grain size and the horizontal drainage height increases.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.588-593
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• 1999

This study were performed to investigated the behavior of excessive pore water pressure with embankment of soft clay. The dissipation behavior of excessive pore water pressure in the improved and non-improved area was used to compare and alyze with lateral displacement , and to investigated the applicability of the methods for stability evaluatio of soft clay. The behavior of excess pore water pressure could be used to the fundamental data for stability evaluation, and the evaluation of the stability of embankment was recommended to use the indlination of curve rather than critical line.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.140-147
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• 2003

There are many problems in the prediction of soil dynamic behaviors because undrained excess pore water pressure builds up and then the strain softening behavior is occurred simultaneously. A few analytical methods based on the dynamic constitutive model have been proposed but the model hardly predict the excess pore water pressure directly. In this study, the verification on the disturbed state concept (DSC) model, proposed by Dr, Desai was performed. Some laboratory tests such as conventional triaxial tests and cyclic triaxial tests were carried out to determine DSC Parameters and then disturbance values are determined by the proposed equation. Through this verification, it is proved that the disturbed state concept can express reliably the soil dynamic characteristics such as excess pore water pressure and strain softening behavior. It is also found that the critical disturbance which is determined at the minimum curvature of disturbance function can be a the specific index.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.107-114
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• 2003

There are many problems in the prediction of dynamic behaviors of saturated soils because undrained excess pore water pressure builds up and then the strain softening behavior is occurred simultaneously. A few analytical constitutive models based on the effective stress concept have been proposed but most models hardly predict the excess pore water pressure and strain softening behaviors correctly In this study, the disturbed state concept (DSC) model proposed by Dr, Desai was modified to predict the saturated soil behaviors under the dynamic loads. Also, back-prediction program was developed for verification of modified DSC model. Cyclic triaxial tests were carried out to determine DSC parameters and test result was compared with the result of back-prediction. Through this research, it is proved that the proposed model based on the modified disturbed state concept can predict the realistic soil dynamic characteristics such as stress degradation and strain softening behavior according to dynamic process of excess pore water pressure.

• Advances in Computational Design
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• 제1권3호
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• pp.265-274
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• 2016

The present paper describes the results of numerical modeling of a dam founded on loose liquefiable deposit using PLAXIS-3D finite element software. Effect of a different dam water level on parameters like displacements, Excess Pore water pressures, Liquefaction potential and Accelerations is studied. El- Centro earthquake motion is applied as input earthquake motion. The results of this study show that different upstream dam water level greatly affects the displacements, excess pore pressure and displacement tendency of the underlying foundation soils and the dam.