• 한국재난관리표준학회지
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• 제2권4호
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• pp.49-57
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• 2009

대구경 강관을 이용한 지하구조물 공사방법은 교통지연 및 안전사고 가능성이 높은 지하시설물 공사에 대해서 지상 교통상황에 영향을 최소화 할 수 있는 비개착 터널공법으로 시공단계별 구조적 안전성 확보가 중요하다. 본 연구에서는 상용구조해석 프로그램인 ANSYS를 이용하여 공법의 주요 부재인 대구경 강관의 관경별 구조적 거통특성을 분석하였다. 또한, 위험시공단계를 선정하고 위험시공단계에서의 웅력집중부위의 응력상태를 검토하였다. 마지막으로 관경 및 관 두께에 따른 구조물의 거동과 응력상태 변화를 확인하여 효율적인 대구경 강관의 사용을 제안하였다.

• 터널과지하공간
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• 제28권6호
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• pp.620-634
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• 2018

고속도로면으로 부터 심도는 약 7.5 m로 얕으나 너비가 약 21 m로 넓은 터널의 안정성을 확보하고 도로면의 침하를 최소화하기 위하여 NTR(New Tubular Roof)공법을 보조공법으로 이용하였다. 이 방법에 따라 터널 굴착예정선 둘레에 직경 2.3 m의 강관 13개를 종방향으로 압입하고 강관측벽을 뚫어 서로 연결한 후 강관내부와 연결공간을 콘크리트로 채워 라이닝을 먼저 만들었고 라이닝 내부 지반을 굴착하여 터널을 완성하였다. 여러 개의 강관을 순차적으로 압입함에 따라 이완영역이 서로 연결되면서 폭이 점차 넓어지는 공동으로 거동하여 침하증분이 커졌고 터널 폭이 가장 넓은 곳에 강관을 압입할 때 도로면 침하증분은 약 2.2 mm로 최대였으며 라이닝 시공 때 까지의 총침하는 약 7.7 mm이었다. 그리고 폭이 넓은 라이닝 내부 터널을 굴착하면서 약 4.3 mm의 침하가 추가로 발생하면서 시공종료 후 총침하는 약 11.8 mm가 되었다.

• 한국터널지하공간학회 논문집
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• 제5권4호
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• pp.401-409
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• 2003

최근 지속적으로 늘어나는 인구와 교통량의 증가로 인하여 도심지국토이용 및 차도가 포화상태가 되어 지하공간의 활용이 매우 절실하게 되었다. 이에 지하 운송수단 및 지하상가 등 지하구조물이 증가하게 되었으며, 공사로 인한 지상의 교통지연, 불량한 지반조건 등으로 인한 각종 안전사고, 주변환경의 훼손, 소음진동에 의한 수많은 민원 발생 등은 사회적인 문제점으로까지 비약되는 경우가 발생하고 있다. 따라서 본 연구에서는 이런 문제점등을 해결함과 동시에 기존 지히구조물 축조공법으로는 안정성을 확보할수 없는 열악한 지반조건에도 안전하고 경제적으로 지하 구조물을 시공할 수 있도록 N.T.R.공법을 수정 보완하였다. 기존의 터널굴착 공법에서 많은 문제점으로 나타난 천정 및 벽체부의 누수문제와 이로 인한 안전성감소, 그리고 장기적인 유지보수 문제 등 시공상의 여러 단점을 보완하여 국내실정에 적합한 N.T.R. (NEW TUBULAR ROOF)공법을 개발하게 되었다. 본 논문에서는 N.T.R.공법 적용 구조물에 대한 수치해석의 결과와 현장 계측자료를 토대로 N.T.R.공법의 특징, 시공방법 및 국내 지하공간개발 적용가능성에 대하여 정리하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.973-981
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• 2008

This document presents the JES(Joint Element Structure) method that has been adopted for the firs time in our country for the construction of the structure crossing under the railroad without open excavation. Front Jacking Method, Tubular Roof Construction Method, New Tubular Roof Method and Joint Element Structure Method are commonly used for the construction of structures crossing under the railroad. JES Method, frequently used in Japan recently, is a new method to construct the structures crossing under the railroad in a safe manner and in a relatively short period of time by utilizing the steel elements with the joints through which the load in the vertical angle to the axial direction is transferred to the next element. The elements are tied to each other through the joints to form the permanent walls of a Rahmen structure under the road without open excavation and without limitation to the length in a convenient way. Through the case study in the project of a Subway Box Culvert Improvement for the Gyeonguiseon Railroad in front of Yonsei University using the JES Method, the cost and period of construction in various types of soil is investigated compared to the Front Jacking Method. Furthermore, by analyzing the results of instrumentation measurements carried out throughout the construction, comparison between the actual displacement in the ground and the predicted displacement in the design is made to provide the considerations to be counted for the design. In conclusion, comparison in the field of economic feasibility, constructability and safety between the JES Method and Front Jacking Method, which is most frequently adopted in our country at present, is made to present the JES Method as a new alternative for the non-open excavation construction method for the structures crossing under the railway.

• Geomechanics and Engineering
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• 제29권3호
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• pp.229-236
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• 2022

In this study, a model experiment and field experiment was conducted to introduce the optimal tensile force when constructing a non-open cut tunnel according to the ground conditions of sandy soil. CMR (Concrete Modular Roof) method is economical because of the high precision and excellent durability, and corrosion resistance, and the inserted parts can be used as the main structure of a tunnel. In addition the CMR method has a stable advantage in interconnection because the concrete beam is press-fitted compared to the NTR (New Tubular Roof) method, and the need for quality control can be minimized. The ground conditions were corrected by adjusting the relative density of sandy soil during the construction of non-open cut tunnels, and after introducing various tensile forces, the surface settlement according to excavation was measured, and the optimal tensile force was derived. As a result of the experiment, the amount of settlement according to the relative density was found to be minor. Furthermore, analysis of each tensile force based on loose ground conditions resulted in an average decrease of approximately 22% in maximum settlement when the force was increased by 0.8 kN per segment. Considering these results, it is indicated that more than 2.0 kN tensile force per segment is recommended for settlement of the upper ground.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.429-435
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• 2003

This paper presents the case studies of Tubular Roof construction Method(T.R.c.M) and Semi Shield method, which were applied to the tunnel excavation under the pre-existing railways. It was proved that T.R.c.M was an effective and safe method for the tunnel excavated in soft soil, giving little damage to the railways located a few meters above. Semi Shield was also performed successfully to bore a tunnel in soft and hard rock, minimizing the ground settlement and tilting of vulnerable fuel tanks. Site and soil conditions are also discussed, which led these relatively new methods to success. Finally, comparison of the measurement results and the design values are made to verify and improve the current design practice.

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.