• Journal of Korean Society of societal Security
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• v.2 no.4
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• pp.49-57
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• 2009

The development and use of underground space in the city have been expanded considerably worldwide due to the growing population and traffic. Because the construction of underground causes some problems including traffic jam and safety accidents, the non-open excavation construction method are commonly used. NTR (New Tubular Roof) method which is one of the non-open excavation method is investigated in this study. The structural safety of underground structures by using NTR method is evaluated by ANSYS 9.0. The tubular roof according to diameters are analysed by ANSYS 9.0 at critical construction step. Finally, according the diameter and thickness of tubular roof the stress nad dispacement are analyzed and then the The efficient use of tubular roof is suggested from relationship between tubular's thickness and stress condition.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.1
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• pp.75-89
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• 2014

In recent years, utilization of underground space has been increasing in various parts of the world. In particular, open-cut method is usually applied to the shallow depth excavation. However some problems such as extreme traffic congestion and unstability of adjacent structures etc. might occur. In order to cope with these problems, the M-CAM (Modified Cellular Arch Method) method was proposed to excavate soil tunnels at shallow depth with secured enough stability and minimized construction period. In this study, sensitivity analysis was performed to predict the influence of the size of CPW(Continuous Pile Wall) and ground conditions on the behavior of the tunnel. First of all, embedded depth and diameter (or thickness) of CPW, coefficient of lateral earth pressure, and ground conditions were selected as parameters that could affect tunnel stability. Meanwhile, FLAC 2D based on finite difference method was used for numerical analysis. As a result of this study, it was checked out that embedded depth among sizes of CPW had a greatest influence on the stability of a tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.4
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• pp.415-429
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• 2013

Performance-based design is becoming a key word for structure design in architectural and civil engineering spheres. In this paper, the need of the performance-based design, especially for tunnels, was enhanced by case study on the largely deformed cut-and-cover arch tunnel built by the prescribed design. In addition, this paper introduces effective method of subdivision on tunnel performance to help field engineer's comprehension. Case study dealing with the issue of typical backwards problem in geotechnical engineering was examined. First of all, the outline of the damaged culvert as well as the surrounding embankment is in detail described. The background, together with the cause of damage, is discussed based on the results of site investigation. Secondly, it was attempted to elucidate the deformation mechanism of the embankment by means of numerical analysis, and the countermeasures are proposed. Finally, the stability of the embankment with the countermeasures was evaluated.

• Explosives and Blasting
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• v.31 no.1
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• pp.33-40
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• 2013

Carinthian cut and cover tunnelling method which combines cut & cover and NATM tunnel excavation method has increased the interest. Design and construction of arch concrete have been increased, but there is no applicable standards for arch concrete. Therefore, in this study numerical analysis was performed to propose standards for the Carinthian tunnelling method considering a variety of conditions such as ground conditions, tunnel overburden thickness, thickness of backfill, and overburden surface slope angle changes, linear regression equations derived to classify and organize a rational, economical, and safe Carinthian cut and cover tunneling method based proposed.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.119-130
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• 2003

This thesis is results of experimental works on the behavior of the cut-and-cover tunnel. Centrifuge model tests were performed to simulate the behavior of the cut-and-cover tunnels having cross sections of national road and subway tunnels. Model experiments were carried out with changing the cut slope and the slope of filling ground surface. Displacements of tunnel lining resulted from artificially accelerated gravitational force up to 40g of covered material used in model tests, were measured during centrifuge model tests. In model tests, Jumunjin Standard Sand with the relative density of 80 % and the zinc plates were used for the covered material and the flexible tunnel lining, respectively. Basic soil property tests were performed to obtain it's the property of Jumumjin Standard Sand Shear strength parameters of Jumunjin Standard Sand were obtained by performing the triaxial compression tests. Direct shear tests were also carried out to find the mechanical properties of the interface between the lining and the covered material. Compared results model tests estimation with respect to displacements of the lining.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1585-1592
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• 2008

산업사회의 발전에 따라 사회 기반시설분야도 복잡다양해지고 특히 도시기능이 활발해지면서 지금의 도심지에는 지하철, 상수도, 하수도, 전력구, 통신구, 지하보차도, 지하상가, 지하주차장 등 여러 가지 용도의 지하공간이 요구되고 있으며, 이러한 지하 구조물을 축조하는데 있어 도로상에 차량 증가로 인한 교통 혼잡이나, 지하매설물의 장애로 인하여 기존의 개착식 공법으로 시행하지 못하고 지하터널공사로 시행하는 경우가 빈번하다. 기존 국내 외 터널공법 관련문헌과 현재 사용되는 터널공법의 실제 시공에 관한 정보를 수집하여 장 단점, 시공시 주의사항, 적용조건등의 조사내용을 바탕으로 RPS 공법을 고안하였다. 소규모 지하구조물을 구축하기 위한 RPS 공법은 출발갱내에서 상부에 파이프 루프를 시공한 후 광폭 유압 패널이 장착된 철제 선도관을 추진시켜 선도관을 원압잭에 의하여 압입한 후 P.C. 콘크리트 구조물을 거치하고 원압으로 압입 추진토록 하였다. 또한, 대규모 지하구조물 축조시에는 구조물 예정상단부에 지반조건에 따라 파이프 루프공법 또는 소구경 Semi-Shield 공법을 이용하여 루프를 시공함으로써 상부의 침하를 방지하고, 측벽은 광폭유압 패널을 이용하여 여굴의 최소화 및 곡선부 시공을 용이하게 하였다.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.4
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• pp.261-276
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• 2002

Recently, for the purpose of choosing reasonable and economical construction, the decision making analyses, such as VE (Value Engineering) and LCC (Life Cycle Cost), are generally performed. But, these methods have some limitations for the application to subway tunnel construction method. So, the AHP (Analytical Hierarchy Process) analysis is applied to determine relative importance for obtaining objectivity in quantitative analysis. And, the LCSC (Life Cycle Social Cost) method is developed to account for the social loss and risk by tunnel construction. From the case of the subway ${\bigcirc}{\bigcirc}$ lot, those methods are very useful to decision making analysis. And, in that case, both quantitative and quantitative analysis appraisement, the drilling and blasting method is evaluated useful alternative proposal in comparing with the cut and cover method.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.397-419
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• 2012

The pressurizing support tunneling method has been developed that overcomes shortcomings of conventional trenchless methods and applied to the field. The main concept of the new method is the pressurization system which, by means of pressurization bag between outer flange of steel ribs and excavated perimeter, applies higher pressure than the pressure relaxed by excavation to the ground to prevent ground displacement. The stability of the support members and effect of displacement control of the new method were verified through 3D numerical analyses. The new method was applied to the construction of a 10.7 m wide, 7.9 m high and 85 m long ramp tunnel that passes under ${\bigcirc}{\bigcirc}$ Expressway. By applying the new method, the tunnel construction was successfully completed in 13.5 months which decreases construction time to 35% compared to conventional methods, and ground displacement was almost negligible.

• Land and Housing Review
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• v.7 no.4
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• pp.261-269
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• 2016

Pipe-roof method is one of the mostly used method to prevent the ground subsidence during the tunnel construction. As pipe-roof method has made technical advancement and performance improvement, it suggested to utilize pipe-roof to a permanent support system rather than a temporal pre-reinforcing method. Therefore, in this study, pipe-roof method is numerically simulated using finite element method to evaluate effects of pipe-roof on behavior of ground and structure. Analyses are performed considering two major conditions that are with and without the application of pipe-roof and the shape of tunnel cross section. The results are presented with respect to variation of settlement and vertical stress distribution. Based on this results, it is found that ground settlement above the shallow tunnel can be considerably reduced by application of pipe-roof system. Also, the shape of tunnel cross section can influence on the mechanical behavior of ground and structure.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.67-75
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• 2014

In this study, the staged seismic performance evaluations were conducted to the 91 high speed railway tunnels in use for checking whether to comply with the recent design criteria or not. In addition, the seismic fragility functions of the tunnels were developed to allow the probabilistic risk assessment. The results of the staged seismic performance evaluations which consist of a preliminary assessment and a detailed assessment, show that the tunnels comply with the recent design criteria. With reference to the results of previous studies, a form of the proposed seismic fragility functions was set as a log-normal distribution by PGA, and the parameters of the functions were determined by using the probability of damage for the design PGA level. The seismic fragility functions were developed for each types (Cut & Cover, NATM) of tunnels. The seismic fragility functions from this study and the existing research results (FEMA, 2004) were compared to evaluate the seismic performance level of the tunnels, as a result the tunnels of this study were relatively superior to the ASSM tunnels on the seismic performance.