• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.170-180
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• 2008

Successful design, construction and maintenance of NATM tunnel demands prediction, control, stability guidelines, the estimation pre-improvement support system and monitoring of surface settlement, gradient and ground displacement with high accuracy. Moreover, urban NATM tunnel under difficult geotechnical conditions is important the estimation and necessary of pre-improvement support system. Various strategies have been proposed for the quantitative estimation of pre-improvement support system. This paper was investigated and analysed an assessment technique for the quantitative estimation of pre-improvement support system on underground space, as mountain and urban tunnel, in detail. The analysis performed on design and construction stage with field database using the proposed stability estimation index by many researcher including the critical strain and the apparent Young's modulus concept.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1132-1139
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• 2010

The steel pipe of steel-concrete composite piles increases the pile strength and induces the ductile failure by constraining the deformation of the inner concrete. In this research, the load-movement relations and the reinforcement effect by the outer steel pipe in the steel-concrete composite pile were analyzed by performing three-dimensional numerical analyses, which can simulate the yielding behavior of pile material and the elasto-plastic behavior of soils. The parameters analyzed in the study include three pile materials of steel, concrete and composite, pile diameter, pile distance and loading direction. As the results, the axial capacity of the composite pile was about 73% larger than that of the steel pipe pile and about 14% larger than that of the concrete pile. In addition, the horizontal movement at the pile head of the composite pile was about 51% of that of the steel pile and about 19% of that of the concrete pile.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1309-1314
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• 2010

우리나라는 전 국토의 70%가 산지로 구성되어 있어 도로준설 시 절토사면이 필연적으로 발생한다. 그러므로 사면의 안정성확보를 통해 인명피해와 경제적 손실을 막기 위해 보호 및 보강공을 실시하게 된다. 표면보호공법은 절토사면이 조사시점을 기준으로 안전율을 확보하고 있으나, 향후 우수나 풍화진행 등으로 안전율의 감소 방지와 예상치 못한 낙석 등에 대처하기 위한 공법이다. 그러나 식생공, 숏크리트 등의 표면보호공법 시공시 경사방향에 따른 일조량의 차이로 인해 구조물들의 변형 및 유지관리상의 문제점을 야기하고 있다. 식생공의 경우 사면방향이 북향일 경우 일조량의 부족으로 식생들이 정착을 하지 못하게 되고, 이때 사면은 표면보호기능이 상실되어 우수나 풍화진행 등으로 안전율이 감소하게 된다. 숏크리트의 경우는 남향의 사면에서 주간에 일조량이 과할 경우 열에 의해 팽창되고 주?야간 팽창 수축을 반복하여 대류열차에 의한 균열이 발생하게 된다. 이때 숏크리트가 파손되어 도로로 유입시 교통안전에 위협을 가하기도 한다. 이에 본 연구에서는 사면방향에 따른 표면보호공법 선정시 문제점을 논의해 보고 그 방안을 모색하고자 한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1286-1293
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• 2010

The ground anchor used in domestic area, which resists by adhesion between anchor body and the ground to the external force, seems not to be adequate for soft ground and urban area where the boundary between structures is close because the ground is disturbed and lost its strength during boring. In order to overcome such a shortcoming an expanded anchor system has been developed. The ground expansion is accomplished by means of Pulse Discharge Technology. In this technology, a high voltage of electricity is stored and discharged in milliseconds which induces high pressure acting on the ground. By making a couple of bulbs, a passive resistance as well as shaft resistance are mobilized, and therefore a higher pullout resistance comparing existing ground anchors is developed.In this study, a couple of full scale tests were conducted in order to figure out how much the resistance of an expanded anchor increases comparing to the straight. As a result, it was found that a remarkable increase in ultimate pullout capacity is observed for the soft ground and as the number of bulb increases. In addtion, as a result of applying to a cut slope reinforcement, it appeared that the length of fixed zone of anchor can be reduced effectively.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.359-365
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• 2008

As housing supply ratio has become over 100%, the strategic vision of government's policies has been changed from new construction to maintenance and regeneration of old architectural-structures. This fact has brought a light on the reconstruction and remodeling industries and a need for retrofit and rehabilitation techniques of existing foundation. Various methods of foundation for architectural-structures do exist. Among them, micropiling technologies are increasingly applied in foundation rehabilitation and seismic retrofitting projects. Micropiling techniques provide environmental-friendly methods for minimizing disturbance to adjacent structures, ground, and the environment. The installation is possible in restrictive area and general ground conditions. The fact that the installation procedures cause minimal vibration and noise and require very low ceiling height makes the micropiling methods to be commonly used for underpin existing structures. Specialized drilling equipment is often required to install the micropiles for existing basement facilities. This paper presents a case study in which micropiles were constructed to support a superstructure for vertical extension of existing elevator core and provide accessibility to underground parking lot. It is intended to become useful reference for the similar remodeling project.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1224-1239
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• 2008

The earth retaining walls using stabilizing piles can be applied to shallow excavation works without any stiffener. But, It demends a variety of installed composite stiffener on the earth retaining walls when it is installed as deep excavation works. Because, it causes an excessive displacement of walls. This research tried to overcome the problems created by the above issues and intended to apply the composite stiffener. The model test, focused on the effect of installed composite stiffener, measured the bending stress with stabilizing piles and walls, the settlement of earth surface, the displacement of walls for a step excavation and an increase in strip load. With the test results and soil deformation analysis, the reinforcement effect(relating to control displacement and earth presure) was analyzed in a qualitative and quantitative manner. It is expected to overcome a deep excavation works.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.1351-1358
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• 2008

This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is quite open used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with the results of finite element analysis.

• 한국지반환경공학회 논문집
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• 제19권7호
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• pp.13-18
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• 2018

최근 도심지를 중심으로 도로함몰이 증가하고 있어 시민들의 안전을 위협하고 있다. 도로 하부에는 상하수도관로, 전기통신시설 등 각종 도로시설물이 매설되어 있는데 이 시설물의 노후화가 도로 함몰의 원인으로 작용하고 있다. 특히, 도로함몰의 주된 원인으로 주목받고 있는 노후 하수관의 경우 단순히 매설연도에 의존하여 하수관 교체 및 보수보강 등의 관리가 이뤄지고 있으며, 하수관 상태에 의한 도로함몰의 위험성은 고려되지 않는 실정이다. 따라서, 본 연구에서는 다양한 하수관 제원 및 주변 환경 정보 및 CCTV 탐사 결과 및 GPR 탐사 결과를 고려한 신뢰성 있는 도로함몰 위험도 평가 방안을 제시하고자 하였다.

• 한국지반신소재학회논문집
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• 제8권4호
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• pp.47-51
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• 2009

우리나라의 자연재해는 대부분 풍수해에 의해 발생하며, 강우시 산비탈이 갑작스럽게 붕괴되는 산사태로 인해 큰 재난을 겪고 있다. 사면파괴를 유발하는 요인은 다양하고 요인들이 서로 관련이 있기 때문에 어느 하나의 요인에 의하여 사면파괴의 발생을 설명할 수는 없으나, 외적요인 중 강우는 가장 중요한 외적요인이다. 따라서, 본 논문에서는 무보강된 일반사면과 친환경 호안구조물로 사면보호공법이 적용된 사면을 대상으로 실내 강우재현실험을 수행하였으며, 강우강도와 사면경사에 따른 유출량과 저류량을 분석하여 호안구조물의 침식에 대한 사면보호효과에 대하여 검토하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.838-845
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• 2006

Recently construction work in Korea, demands of favorable condition ground had been increased with industrialization acceleration and economic growth. However, because of limited land space, it was so hard to ensure favorable condition grounds that construction work proceeds until soft ground area on plans of road, railroad and industrial complex. In this case, soft ground improvement was required such as a stone column method. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, evaluates the stone columns reinforced by geogrid for settlement reduction and wide range of application of stone columns. Triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate. Then, 3-dimensional numerical analysis were conducted for application of stone column reinforced by geogrid as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on reinforcing depth change of geogrid.