• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.3
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• pp.227-239
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• 2003

For environment-friendly construction, cut-and-cover tunnels have been constructed, thereby leading to embankment slopes with a number of steps. The slopes cause eccentric load on concrete lining of the tunnel. Nevertheless, uniform vertical and horizontal earth pressures, which are determined by considering a self-weight of embankment and $K_0$, are routinely used in structural calculation. Distribution of the earth pressures applied to the lining will lead to a biased calculation far from the actual behavior of the lining. In this study, basic study, therefore, was performed to consider the eccentric load properly in design and analysis of a cut-and-cover tunnel. A method capable of considering the eccentric load in design was proposed and its applicability was numerically examined through a number of examples.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.113-128
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• 2004

To investigate major influencing factors on earth pressure acting on an arch-shaped cut and cover tunnel, Monte Carlo simulation based quantitative sensitivity analysis was carried out for mechanical properties of ground as well as excavation configuration-related design factors. From the sensitivity analysis, it was intended that effects of earth pressures from different influencing factors on a cut and cover tunnel should be numerically identified. Output factors used in the sensitivity analysis such as vertical and horizontal earth pressures at different tunnel positions were obtained from the finite element analysis. In this study, it was revealed that depending upon positions where horizontal as well as vertical earth pressures were acting, they were differently influenced by the same input factors. In addition, earth pressures acting an cut and cover tunnel depended mainly on the embankment at crown and the inclination of cut slope.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.1
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• pp.43-54
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• 2003

In the deign of cut and cover tunnel, the structural analysis such as rigid frame analysis has been used for its simplicity and convenience. The structural analysis, however, can not consider the geological and geotechnical factors such as soil arching effect. In this study, the dominant factors influencing the behavior of cut and cover tunnel such as interface element, slope of excavation plane, distance between slope and tunnel lining, and location of slope of covered soil, were investigated by the numerical analysis to develop the analysis technique and design technology. Based on the results, the variation of bending moment, shear stress, axial force and displacements were evaluated and analyzed for each factor.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.1
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• pp.79-90
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• 2002

The structural analysis such as rigid frame analysis has been used for the design of cut and cover tunnel due to its simplicity and convenience. This analysis, however, could not account for the geometrical factors such as interface elements, slope of excavation plane, distance between lining and excavation plane, etc. To develop the analysis technique and design technology for the cut and cover tunnel, in this study, the numerical analyses considering not only geometrical but geotechnical factors are conducted. Especially, the effects on the mechanical behaviors of cut and cover tunnel due to the slope of excavation plane and the distance between lining and excavation plane are mainly focused in this study.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.3
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• pp.287-301
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• 2009

The novel cut-and-cover tunnel construction method using rib-reinforced pre-cast arch segments has been recently developed and applied for practice to secure a structural stability of high covering and wide width section tunnels. Cut-and-cover tunnels are usually damaged by the seismic behavior of backfill grounds in case of a low covering condition. Seismic analyses are performed in this study to characterize the dynamic behavior of rib-reinforced pre-cast arch cut-and-cover tunnels. Seismic analyzes for 2 lane cast-in-place and rib-reinforced pre-cast arch cut-and-cover tunnels are carried out by using the commercial FDM program (FLAC2D) considering various field conditions such as the covering height embankment slope and excavation slope. It can be concluded that the amplification of seismic wave is reduced due to an increase in the structural stiffness induced by rib-reinforcement. The results show that the rib-reinforced pre-cast arch cut-and-cover tunnels are more effective against the seismic loading, compared to the cast-in-place cut-and-cover tunnels.

• Tunnel and Underground Space
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• v.13 no.2
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• pp.125-137
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• 2003

Field measurements were carried out in this study to investigate the behavior of cut and cover tunnel such as the distribution and the magnitude of the earth pressure during back fill process. Three kinds of measuring instruments, such as the earth pressure load cell, the concrete strain gauge and the reinforcing bar meter of embedded type in concrete structure were installed and measured. Earth pressure load cells measured the outside forces acting on the tunnel lining with radial directions. Three load cells were installed at the crown, the right and the left shoulder of the tunnel, respectively. Three sets of reinforcing bar meter were installed in the double reinforcements of the tunnel lining and their locations were the same with the position of the earth pressure load cells. Concrete strain gauge was installed only one site of the upper compressive part at the tunnel crown. Based on the measurements, the deformation and the earth pressure acting on the tunnel lining were investigated with the back fill process. Considerations on the validity of the field measurements were paid.

• Explosives and Blasting
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• v.27 no.1
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• pp.62-78
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• 2009

Recently, construction techniques have been rapidly developed with reconstruction of old buildings, urban regeneration and efforts of restoring natural ecology, so demolition of deteriorated buildings has been rapidly increasing. Demolition work of building should be executed without damaging surrounding environments according to relevant regulations. There are various demolition methods and among them, explosives demolition is the most practical way for expenses and safety of work. As a part of Daejeon stream ecological restoration project, this thesis is a case of executing demolition of Chung-Ang Department Store which was built 35 years ago as covered structure on the upper part of Daejeon stream with explosives demolition. This structure is 8 stories high, total height of 41.6 m including basement floor, $1,650m^2$ for building area and $18,351m^2$ for total floor area. It is located in the center of Daejeon city where shopping centers and buildings are crowded and main facilities are Daejeon subway (18m), backside shopping center (20m), underground shopping center(15m), Mokchuk bridge, Eunjung bridge(0.25m) and fiber-optic cable(0.25m). In this project, implosion was selected for explosives demolition methods by considering this area being a busy urban area, and this project was executed after examining collapse movement of structure in advance using simulation program not to damage main facilities. Total 80kg of explosives and 1,000 detonators were being used. This project will be a good case of executing explosives demolition successfully by applying implosion on urban area in the country.

• Proceedings of the Korea Water Resources Association Conference
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• 1993.07a
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• pp.107-113
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• 1993

도시가 발달함에 따라 늘어나는 교통량과 주차공간 등의 부족을 해소하기 위해 하천에 교량을 증설하건 복개를 하는 경우가 많아지고 있다. 이와 같은 현상은 수리학적으로 바람직한 현상이 아니므로 과연 하천에 장애물을 설치할 경우 이들 장애물에 의하여 하천 흐름이 어떻게 영향을 받는지를 실험적으로 분석해 보았다. 모형은 중랑천과 한천로상의 교량 형태를 점검하고 이들을 7개의 형태로 분류 1/50의 축척을 사용하여 제작하였다. 실험장치는 국립 건설시험소에 있는 직선 개수로를 이용하였으며 실험을 위하여 하천의 경사는 1/500, 1/750과 1/1000을 그리고, 하천 유량은 200, 350, 500 CMS를 각각 선택하였다. 하천에 교량의 장애물 설치시 구조물 형태에 따라 6~30%의 수위 상승효과가 있었으며 표면 유속은 7~23%의 감속 효과가 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1965-1970
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• 2009

본 연구에서는 하천 물리모니터링 결과를 바탕으로 청미천 유역의 본류에 대한 하천 수변환경을 평가하였다. 평가 지침은 수생태 건강성 평가에서 제시된 지침을 따랐다. 평가 결과, 죽산천과 청미천 합류부 지점은 2등급으로 생태서식 여건이 좋은 편으로 나타났다. 모래로 된 교호사주가 좌우안 넓은 지역에 걸쳐 형성되어 있고, 하중도 및 식생 사주도가 형성되어 식생활착이 왕성하며, 주로 달뿌리풀 위주의 군락이 형성되어 있었다. 특히 합류점 상류 본천은 자연하천의 모습을 간직하고 있었으며, 양안에는 식생과 수목이 왕성하게 자연적으로 형성되어 있었다. 화봉천과 청미천 합류부 지점에서의 수변환경 모니터링 조사 결과, 하도는 정비되어 있으나 저수로는 사행을 유지하고 있으며, 제외지의 토지이용 상태와 하천 복개율 및 횡방향 인공구조물 상태는 비교적 바람직한 것으로 나타났다. 하도 내 저수로는 호안공이 설치되지 않고 흐름의 다양성 자연스럽게 형성되어 있다. 이 지점은 하천환경이 비교적 잘 보전되어 있어, 지속적인 보전을 위한 유지관리가 요구된다. 특히 죽산천에 축산 농가 및 시가지의 확장으로 오염원이 증가되고 이들이 하천으로 유입될 우려가 있다. 생태환경을 보전하기 위한 비점오염원 유입 차단 및 수질개선 대책이 우선시되어야 할 것으로 판단되었다.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.564-569
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• 2005

Usually, Steel pipe grouting method or cut and cover method has been applied to tunnel with very shallow overburden or it is situated in valley. However, in case of lack of overburden height to reinforcement tunnel crown which is very difficult to construction. Also, application of cut and cover method that do not consider surrounding site condition causes popular enmity generation and environmental damage. It is the best alternative method that reduces the amount of excavated soil and excavate tunnel under ground to solve these problems. The tunneling method using cover structure which is to prevent a tunnel from collapse because this method can be reduce excavation area and construct tunnel under ground after set a cover structure and backfill ground. In this study, to know more effective structure type, comparative analysis was performed to behavior characters of slab and arch type construction that can be used to cover structure. Also a 2D and 3D numerical analysis have been performed to verify the stability of ground during excavation. As the result, the tunneling method using cover structure that it can be good alternative method for tunnel with shallow overburden and it through valley