• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1061-1064
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• 2010

뒷채움재료의 선정기준으로 구조물과 연이은 토공부 사이의 부등침하를 최소화하기 위해 맞물림(Interlocking)효과 및 다짐성이 우수하고 배수가 원활히 될 수 있는 입상재료인 선택층 재료를 사용하는 것으로 규정 및 설계하고 있다. 일률적으로 정해진 현재의 뒤채움재료 선정기준은 건설초기에 손쉽게 구할 수 있었던 선택층 재료인 SB-1의 공급이 어려워져 적절하게 현장여건을 고려하기 곤란하다. 공학적 측면에서 지나치게 안전측으로 선택 및 설계되는 경우가 있어 공사비의 상승 등 시공성과 경제성 측면에서 많은 문제점을 가지고 있다. 본 연구에서는 실내 모형토조를 이용하여 뒤채움 완료 후 뒤채움부 상단에서 교통하중에 의한 장기동적토압을 모사해 뒤채움부의 장기 침하량과 수직, 수평토압을 측정 비교해 교대 뒤채움부 재질 변경을 위한 기초자료로 활용하고자 한다.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.856-861
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• 2010

In recent days, the safety of the levee has been an issue because the levee has become bigger according to the Four-river Restoration Project and so on. The greater part of the levee damage has occurred in the interface between soils and the structures. Specially, the drainage construction crosses the levee keeps its settlement down in order to secure a grade of drainage. However, when the settlement isn't generated by using foundation such as pile, the levee is more likely to have leakage at the interface because the construction doesn't behave with soils. In our study, therefor, testing of the behavior of the levee having the drainage construction was carried out to clarify the effects of the foundation type of drainage construction.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1094-1103
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• 2010

The safety of pile foundation is getting declined when the pile foundation acting on lateral load is exposed by dredging. So appropriate reinforcement is needed for stability secure. Thus, in this study, the stability variation and reinforcement range caused by dredging is estimated on the basis of down scale test. The scale effect is determined by real scale numerical analysis. the behavior of pile by dredging stages is estimated by load control type. The credibility is verified through the comparison between down scale model test and numerical analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1172-1177
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• 2010

For the deep excavation in urban area, the braced-cut method is mainly adopted. In this case, inadequate consideration of ground water level may result in wrong prediction of structural behavior. In this study, the effects of hydraulic interaction between wall and grout were investigated using the finite element method. The maximum stress in case of confined ground water condition is obtained at the final excavation stage in the range of 70~80% of excavation depth. The stress of impermeable case is about 50% larger than that of permeable case. When the relative permeabililty of wall-grout become smaller, the stress is getting bigger. And the stress tends to converge in case of 1/100 or less of the relative permeability.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1294-1301
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• 2010

This study is an experimental research for the dispersion behavior and impact characteristics of debris flow according to change of slope. Large scale experimental setup for the debris flow was established to simulate the artificial rainfall and control the ground slope. Parameters such as materials of debris flow, slope, and length of slope were used for the experiments. After the experiments, it was found that the speed of ground material components was increased about 28~47%. It was found that speed can be increased by increasing the particle size. Furthermore, maximum/final loads for ground material components were increased 89% for the coarse aggregate and 68% for the fine aggregate comparing with sand.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1382-1387
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• 2010

A 3D FEM numerical analysis was performed to observe the changes of supporting system of a old 1-lane tunnel when it is enlarged to 2-lane, 3-lane and 4-lane. The standard Type-III supporting pattern was applied to the new tunnel because the ground was assumed as Type-III. The observation was carried out at the middle supporting system of the old 1-lane tunnel alignment. The results shows that the changes of old tunnel supporting system began when the new tunnel was excavated at 2D(D is the equivalent diameter of 1-lane tunnel) behind of the observation place and became very rapid from 1D.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.51-58
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• 2008

The George Massey immersed tunnel passes the Fraser River near Vancouver, Western Canada. In this paper, dynamic analysis of the tunnel on sandy soils was performed using an effective stress constitutive model called UBCSAND. This model is able to calculate pore pressure rise and resulting tunnel deformation due to cyclic loading. Centrifuge tests conducted at RPI are used to verify the model performance. Centrifuge tests consist of 3 models: Model 1 is designed for an original ground condition, Model 2 for a ground improvement by compaction method, Model 3 for a ground improvement by gravel drainage. The results of centrifuge Model 1 are presented and compared with predictions of UBCSAND model. This model well captured the results of centrifuge test and therefore can be used to predict dynamic behavior of similar tunnels or underground structures on sandy soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.692-700
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• 2007

There are several types of foundations for light-weight structures, such as low story buildings, on soft clay deposits. Those foundations, such as piled raft, compensated foundation, mat foundation, floating foundation are commonly used rather then end-bearing piles to get more benefits on the construction and cost savings. In this study, settlement behaviors are computed and compared for several types of foundations on soft clay deposits. Also, theoretical expressions of parameters for piled raft system were provided with co-relations for design purposes. The predictions of settlements of piled rafts foundation are proposed based on the pile dimensions and design loads. From this study, the piled raft foundations is more benefits for reducing the settlement of clay deposits, and it is found that the piled raft system is applicable and effective on thick clay deposits, and that differential settlements of the foundation should be managed by designing the configuration of pile lengths.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1012-1023
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• 2008

This paper estimates the long-term settlement of In-cheon unsanitary solid waste landfills. which is 20 years old. The unsanitary solid waste landfills was subjected to pre-loading system over a period of 1 year, and the settlement for 300 landfill monitors provided measured data. This landfill contain relatively small amount of organic component, therefore the initial stage of settlement was very small. The existing settlement models are examineed to compare with the observed behavior of this site and, also to estimate long-term settlement. The Hyperbolic, Bjarngard & Edgers, and Power Creep Law models showed good agreement well with the measured settlement of the In-cheon unsanitary solid waste landfills.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.55-77
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• 2007

Currently a large number of high rise building projects are under plan and a mega foundation system to support this high load with safety is requiring. The foundation of a highrise building is displaced by the building load, which influence the behavior of a super structure in reverse. In this aspect, the structural interaction analysis between a foundation and a super structure is necessary. In this study, the relationship of a superstructure of building and a foundation has been reviewed, considering the tendency of design from a capacity driven design to a performance design. Two different case studies have been introduced to help understand this relationship in more specific, the first case is the high rise building founded on a mat system on rock and the second is that on large diameter bored piles on soft ground condition.