• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2002.10a
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• pp.1-15
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• 2002

동복터널의 현장지질은 편마암과 석탄층(Coal Beds)이 협재된 암질이 매우 불량한 편암으로 구성되어 있으며, 설계 시에는 석탄층의 발달이 확인되지 않아 그 영향을 충분히 고려되지 않았다. 석탄층(두께 2~8m)은 편암의 Rock Cleavage와 같은 방향과 45~55도의 경사를 가지며 pinch out and swelling 형태로 발달이 불규칙하다. 하행선굴착 중 약 290m구간에 걸쳐 석탄층이 나타났으며, 90m 구간은 천단 및 측벽부에서 집중 발달되어 쳐대일변위가 20mm이상인 지점이 발생하는 등 상반굴착 시 111.2mm의 수평방향 내공변위가, 하반굴착 시에는 최대 127.8mm의 내공변위가 발생하였고 하반관통이후 수렴되었다. 내공변위 과다발생에 대한 대책으로 지보타입을 하향 조정하였고 측벽부는 하향 록볼트를 포함한 추가록볼트 보강을 실시하였다. 한편 터널 바닥부의 석탄층은 도로포장 후 침하문제가 예상되어 인버트를 기존 강지보공과 H-beam으로 연결.폐합한 후 콘크리트로 치환(140m구간)하여 추가변위를 최소화하였으며 무근콘크리트로 설계된 라이닝은 철근콘크리트 라이닝으로 변경 시공하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.428-431
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• 2005

In this paper, the displacement and stress of pile foundation constructed in the soft cohesive soils were measured and investigated at each construction phase. The piles belongs to compressive stress then extension due to lateral flow of soft soils. Battered piles showed different stress state according to construction direction. The lateral displacements of piles radically occurred at the embankment phase.

• Tunnel and Underground Space
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• v.18 no.5
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• pp.338-342
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• 2008

Longitudinal deformation profile(LDP) has been obtained mostly by numerical analysis. In this study, LDP was plotted by measured data from horizontal inclinometer and crown settlement. Deformation of foe ahead was determined by comparing to the maximum deformation point and deformation of after excavation was determined by regression of the measured crown settlement data. The result shows that crown deformation began as f3r as 3D ahead of the face. Crown settlement at the face was 40% of ultimate deformation, which was 10% higher than numerical results, and the deformation converged after excavation of 4D.

• Journal of the Korean Geotechnical Society
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• v.21 no.3
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• pp.43-54
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• 2005

The ground movements during three. full-scale trial diaphragm wall (DW) panel constructions were monitored and analysed. The DW panels were constructed in reclaimed fill where sedimentary marine deposit and residual weathered soils are being consolidated. The monitoring data showed exceptionally large lateral ground movements of up to 293 mm near a trench due to the DW panel constructions, which is about 0.8$\%$ D, where D is the maximum excavation depth. It was observed that deliberate holding period of the trench resulted in a significant increase in the lateral ground movements of about 50-225$\%$. A pre-treatment of the marine deposit by installing a single line of jet grout columns around the trench prior to the excavation was found to be a very effective way of reducing the ground movements. The measured ground settlements were compared with some relevant case histories. DW panel constructions in sedimentary marine deposit are likely to cause maximum ground surface settlement up to 0.225$\%$ D.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.87-99
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• 2023

Ground excavation inevitably causes ground displacement of adjacent ground, and structures and facilities exposed to ground displacement may suffer various damages. Therefore, in order to minimize the damage and damage to adjacent structures and facilities caused by excavation, ground displacement (settlement and horizontal displacement) in the adjacent ground caused by excavation must first be predicted. There is many ground displacement information induced by general braced cut excavation, but the information is not enough for circular shaft excavation. This study aims to provide information on the estimation of ground settlement caused by circular shaft excavation through the case analysis of circular shafts and comparison with braced cut excavation. From this study, it was found that the use of the settlement criterion of braced cut excavation as the settlement management criterion for circular shaft excavation is a conservative approach in terms of safety. But when considering the economic aspect, it may result in overdesign of the wall and therefore, a more reasonable settlement criterion can be needed for circular shaft excavation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.141-149
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• 2006

For application of NATM, the self-supporting until installation of the supporting system must be satisfied. However, the face of a tunnel are always unsupported and therefore it is fairly vulnerable to tunnel collapses. Face blots are well known and widely used to prevent the deformation of the tunnel face and its circumference, which are installed horizontally toward the tunnel axis generally. To maximize the supporting effect of face bolts, this study has analysed the effective design patterns of face bolts by changing their installation angles. As the conclusion, it has been found that the axial displacement of the face increases slightly by installing the outermost bolts upward from the axis but surface settlement at 2.5D behind the face decreases up to 18%.

• Journal of the Korean Geotechnical Society
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• v.27 no.12
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• pp.97-106
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• 2011

To analyze the lateral load-deflection behavior of steel-concrete composite drilled shafts, a series of lateral pile load tests were performed. The test results were compared with the results from various analytical methods for lateral pile behaviors using the coefficients of subgrade reaction ($k_h$) estimated by pressuremeter test (PMT) and standard penetration test (SPT). As a result, it was found that the analytical methods using the $k_h$ estimated by SPT N value were not suitable for evaluating the pile head lateral load-deflections of the piles within the allowable deflection. However, the methods using the $k_h$ calculated from PMT were able to represent the initial lateral behavior at the head of the piles fairly well. Also, the method by the pressuremeter curve, which was applied directly to the p-y curve of the piles, offered a reasonable lateral behavior estimation by applying the correction factor to the pile materials.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.6
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• pp.45-52
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• 2018

The paper aimed to find out the lateral behavior of outrigger system in high-rise building considering floor diaphragm. To achieve this goal, a structural schematic design of 80 stories building was conducted by utilizing MIDAS-Gen. In this research, the key parameters of the structure analysis were the outrigger location in plan, the slab stiffness, the outrigger stiffness and the kind of diaphragm. For the purpose of this study, we analyzed and studied the lateral displacement in top floor, the story drift and the stress in slab. The research results indicated that the outrigger location in plan, the slab stiffness, the outrigger stiffness and the kind of diaphragm had an effect on lateral behavior in outrigger system of tall building. And the results of this analysis research can provided the assistance in getting the basic data of structure design for looking for the lateral behavior of outrigger system in the high-rise building.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.179-188
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• 2018

A new style of panel-type reinforced earth wall is a more integrated structure by connecting the geosynthetic strip reinforcement with a folding groove directly to the front panel through C-shaped insertion hole embedded in the panel. In this study, field measurements were conducted on two reinforced earth walls constructed at different sites to assess the field applicability and structural stability of the new style of panel-type reinforced earth wall. The horizontal displacement of the front panel, tensile deformation of the geosynthetic strip reinforcement, and horizontal earth pressure acting on the panel were measured and analyzed through the field measurements. According to the field measurements, after completion of the reinforced earth wall construction, the maximum horizontal earth pressure applied to the front panel was less than two-thirds of the Rankine earth pressure, and the maximum horizontal displacement of the front panel was less than 0.5% of the wall height, and the maximum tensile strain generated on the reinforcement was less than 1.0%. Therefore, it was found that two reinforced earth walls constructed at different sites remained stable.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.352-359
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• 2010

Stability of twin tunnels depends on the pillar width and the ground condition. In this study, large scale model tests were conducted for investigating the influence of the pillar width of twin tunnels on their behavior in the regular horizontal jointed rock mass. Jointed rocks was composed of concrete blocks. Pillar width of twin tunnels varied in 0.29D, 0.59D, 0.88D and 1.18D, where D is the tunnel width. During the test, pillar stress, lining stress, tunnel distortion, and ground displacement were measured. Lateral earth pressure coefficient was kept in a constant value 1.0. As a result, it was found that the pillar stress and the displacement of the ground and tunnel were increased by decreasing pillar width. The maximum displacement rate was measured just after the upper excavation in each construction sequence. And the maximum influence position was the right shoulder of the preceeding tunnel at the pillar side. It was also found that for the stability assessment the inner displacement was more critical than the crown displacement. The influence zone was formed at the pillar width 0.59D~0.88D that was smaller than 0.8D~2.0D, which was proposed by experience for a good ground condition. And it would be concluded that horizontal joints could also influence on the stability of the twin tunnels.