• The Journal of Engineering Geology
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• v.2 no.1
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• pp.19-35
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• 1992

aThe elastic properties of the fault zone (width; 3~12m), the shattered zone (width; over 40m) and the fresh rock zone distributed under the core foundation of fill dam in granitic gneiss have widely different range. The deformation moduli of the fresh rock zone, the fault zone and the shattered zone obtained from in situ rock tests - Plate Load Test and Bore Hole Deformation Test - show a range of $42,000~168,000kg/\textrm{cm}^2,{\;}963~2,204kg/\textrm{cm}^2{\;}and{\;}1,238~2,098kg/\textrm{cm}^2$, respectively. The differential settlements hetween the fault zone and the fresh rock zone are expected after the dam construction. Therefore, the displacement of foundation and concrete fill are evaluated using FEADAM 84 program of finite element analysis. The geometric distribution of discontinuifies obtained from the site mapping and drilling is considered in the finite element analysis. The analysis shows that the differential settlements between the fault zone and the fresh rock zone is about 6cm, while that of concrete fill is within 0.5cm.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.255-266
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• 2010

In high-rise buildings, an outrigger system is frequently used as a resisting system for lateral loads. Since the outriggers tie exterior columns and an interior core, exterior columns can participate in the lateral load resisting system and the structural resistance capacity can be increased. However, the outriggers contribute for controlling gravity loads as well as lateral loads. The flows of gravity loads can be changed by the members of outriggers, for the purposes of transferring loads to mega-columns, distributing gravity loads equally among vertical members of columns, walls, or piles, minimizing differential settlements in a foundation system, and so on. In this study, by computational structural analyses of high-rise buildings over 100 floors, the effects of outriggers on controlling gravity loads are analyzed. Analyses for 3-dimensional models with or without outrigger members are performed, and then the gravity load distributions in columns and piles and foundation settlements are analyzed. Also, the effects of outriggers on gravity load controls during construction stages as well as after construction are included.

• Journal of the Korean Geotechnical Society
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• v.21 no.7
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• pp.21-29
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• 2005

This paper presents the results of a numerical investigation on the behavior of a geosynthetic reinforced two-tier segmental retaining wall (GR-SRW) on a yielding foundation. A hypothetical 10 m high two tier GR-SRW to be constructed on an incompetent foundation containing a layer of relative soft soil deposit was considered. A verified finite-element procedure was employed to get insights into the effect of foundation yielding on the wall behavior including the wall deformation and the reinforcement load. It is shown that the effect of foundation yielding is to increase the wall deformation as well as the reinforcement load, thus influencing both the internal as well as the external stability of the wall. Practical implications of the findings obtained from this study are highlighted in this paper.

• Journal of the Korean Geotechnical Society
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• v.24 no.12
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• pp.85-92
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• 2008

It is necessary to develop a rational design method for surface reinforcement of very soft ground because most current design works rely on merely crude empirical correlations. In this paper, the mechanical behavior of very soft ground that is surficially reinforced was investigated with the aid of a series of numerical analyses. Several material properties of each dredged soft ground, reinforcement and backfill sand mat have been exercised in the numerical analysis. The result of numerical analysis was compared with those of the laboratory model test. Through the matching process between the numerical and experimental result, it is possible to determine representative material properties of the dredged soft ground, reinforcements and backfill sand mat. These verified material properties permit to evaluate the effect of the stiffness of reinforcement and the thickness of sand mat on the overall deformation of the reinforced soft ground.

• Journal of the Korean Geotechnical Society
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• v.25 no.5
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• pp.17-28
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• 2009

When embankments are constructed on soft clay deposit, unsymmetrical surcharges due to embankments may generate the excessive vertical settlement and lateral deformation of soft clay foundation. The excessive deformations in soft grounds cause not only stability problem of the embankment itself but also that of the adjacent structures. The objectives of this research are to study the deformational behavior of soft ground due to the embankment load with different loading and soil conditions. Five model tests are carried out with different test conditions. From the results of the model tests, it is concluded that the lateral displacement induced by the embankment load occurs in the range of two times of the embankment width from a toe. In addition, the relationship between loading rate, v, and the vertical settlement of the soft ground, ${\Delta}s$, and the lateral displacement at the toe of embankment, ${\Delta}y_m$, is investigated based on the model test results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2C
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• pp.41-49
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• 2009

Due to the increased size of civil infrastructure and the cost of materials, the needs exists for utilizing large sized cast-inplace piles in lieu of conventional precast piles. Among them, the barrette pile has become more commonly used in fields where a diaphragm wall is the retaining wall, to improve workability and economical efficiency, and to ensure hole stability under deep soil layers. In this paper, the bearing capacity and displacement characteristics of the barrette pile are evaluated by using the bi-directional loading test data obtained from four different sites. In addition, the design value of pile shaft resistance, ${\beta}$, is assessed with previous literatures and load transfer analysis. Finally, numerical analyses were performed to analyze the load-displacement behavior, and the interface effect on the piles, using the 3-dimensional finite element method.

• Journal of Ocean Engineering and Technology
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• v.25 no.2
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• pp.47-54
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• 2011

A piled raft foundation is one of the systems used to reduce the settlement of structures. However, the general design method for a piled raft foundation system assumes that the piles only support external loads, which exclude the bearing capacity of the raft itself. In this study, an experimental model test was performed to evaluate the raft capacity for the external load on the sand. Additionally, a part of the sandy ground under the raft was replaced with a gravel mat to reinforce the piled raft foundation system and increase the bearing capacity. Then, parametric studies of the reinforced ground were performed to determine the displacement and load-sharing ratio of the piled raft foundation system.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.687-696
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• 2005

Safety diagnosis was conducted to evaluate the long-term stability evaluation of power transmission tower of which deformation of the upper structural elements occurred. To assess the cause of the structural deformation, field investigation including BIPS, down-hole test, concrete pile coring and finite element analysis were carried out. From these studies, the major cause of deformation was found due to the heavily fractured layer and weathered soil topography at the pile tip area. The cement-milk grouting method was proposed to reinforce these weak zone around the pile tip area. Also, the increase of cross-section and stiffness for steel members of upper tower structures was suggested. Instrumental monitoring was proposed as well to verify reinforcing effect.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.135-143
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• 2000

고강도 H말뚝은 다른 말뚝에 비해 관입성이 우수하며, 경제적으로 시공이 가능하여 도로공사 및 건축공사의 기초말뚝으로 광범위하게 전세계적으로 사용되어지고 있다. 따라서 본 논문에서는 고강도 H말뚝, 강관말뚝 및 PHC 말뚝에 정재하시험과 동재하시험을 실시하여 허용지지력을 비교 분석하였으며, 각각의 말뚝에 대한 동재하시험을 통해 시간경과효과를 평가하였다. 정재하시험과 동재하시험을 비교 분석한 결과 하중-침하곡선이 유사한 것으로 조사되었다. 또한 고강도 H말뚝, 강관 말뚝, PHC 말뚝이 지반내에 향타되었을 때의 허용지지력은 시간이 경과함에 따라 증가하는 것으로 평가되었다. 재하시험 결과 시간경과효과로 인해 지반의 허용지지력이 상승됨을 알 수 있어 앞으로 기초말뚝 설계시 참고자료로 활용할 수 있을 것으로 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6322-6328
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• 2014

Finite element analyses were performed to find out the load bearing behavior of three kinds of shallow foundations. The analysis results for strip footing showed that local shear failure mode could be observed for a zero dilatancy angle and general shear failure mode could be seen for non-zero dilatancy angles. The ultimate bearing loads for non-zero dilatancy angles were approximately 1.5 times higher than that of a zero dilatancy angle. General shear failure mode was observed for circular footing and square footing regardless of the dilatancy angle. The ultimate bearing loads for a non-zero dilatancy angle were slightly greater than that for a zero dilatancy angle. A comparison of the load-settlement curves for three kinds of footing showed that the load bearing capacities for non-zero dilatancy angle were greater than those for a zero-dilatancy angle.