• 터널과지하공간
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• 제10권3호
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• pp.344-354
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• 2000

지하저장공동에 설치되는 콘크리트 플러그는 기능한 모든 하중조건에 대해 안정하게 유지됨은 물론 저장된 유류의 외부 유출과 지하수의 과다 유입을 방지하는 기능을 수행하여야 하므로 지하 유류 비축기지의 건설 및 운영 단계에서 매우 중요한 역할을 한다. 플러그가 시공되고 나면 외부와의 접촉이 모두 차단되게 되므로 플러그가 그 기능을 제대로 발휘하기 위해서는 설계단계에서부터 역학적 및 수리적 고려가 이루어져야 한다. 따라서 본 연구에서는 2차원 및 3 원 유한 차분 프로그램인 FLAC 과 FLA $C^{3D}$를 사용하여 플러그에 대한 역학적 및 수리적 해석을 실시하였다. 먼저 측압계수의 변화, 심도의 변화, 플러그의 형상변화, 암반과 콘크리트 접촉면의 상태변화, 굴착손상권의 발생 등 다양한 조건 하에서 플러그의 거동 변화에 대한 역학적 해석을 실시하였으며, 2차원 해석조건과 동일한 조건을 가진 3차원 모델을 구성하여 그 결과를 2차원 해석과 비교, 검토하였다. 또한 플러그의 쐐기깊이 변화에 따른 수리해석을 실시하여 그 결과를 비교하였다.다.

• 한국건설관리학회논문집
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• 제5권3호
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• pp.71-78
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• 2004

In conventional method of supporting soil shuttering wall during excavation a system of struts and wales to provide cross-lot bracing is common in trench excavations and other excavations of limited width. This method, however, becomes difficult and costly to be adopted for large excavations since heavily braced structural systems are required. Another expensive and unsafe situations are expected when temporary struts must be removed for the construction of underground structures. This paper introduces innovative strut systems which can be used as permanent underground structures after its role as brace system to resist earth pressure during excavation phase. Underground structural system suggested from architect is checked against the soil lated pressures before the analysis of stresses developed from gravity loads. In this technology, named SPS(Struts as Permanent System), retaining wall is installed first and excavation proceeds until the first level of bracing is reached. Braces used as struts during excavation will serve as permanent girders when buildings are in operation. Simultaneous construction of underground and superstructure can proceeds when excavation ends with the last level of braces being installed. In this paper, construction sequence and the calculation concept are explained in detail with some photo illustrations. SPS technology was applied to three selected buildings. One of them was completed and two others are being constructed Many sensors were installed to monitor the behavior of retaining wall, braces as column in terms of stress change and displacement. Adjacent ground movement was also obtained. These projects demonstrate that SPS technology contributes to the speed as well as the economy involved in construction.

• 화약ㆍ발파
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• 제41권4호
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• pp.17-28
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• 2023

최근 연구시설 및 자원개발 등의 목적으로 지하공간 활용이 증가하고 있으며, 저심도 암반을 넘어 고심도 암반에 대한 개발이 증가하고 있다. 고심도 지하공간 개발은 높은 응력과 높은 온도 조건에서의 암반의 안정성을 고려해야 한다. 고심도의 경우 암반 구조와 불연속면의 상태 등이 안정성에 영향을 미칠 뿐만 아니라 지진 및 굴착을 위한 암반발파에 의한 지반진동 전파가 지하공동의 응력변화를 발생시켜 암반의 안정성에 영향을 미치게 된다. 발파공학 측면에서 지반진동을 예측하는 방법은 실측 데이터를 바탕으로 통계학적 회귀분석을 통한 경험적 회귀모형과 수치해석적 방법이 사용되고 있다. 본 연구에서는 단일공 발파에 의한 폭발압력 전파특성과 지반진동 전파특성에 대한 경험적 회귀모형을 획득하기 위하여 실험적 방법을 통해 연구를 수행하였다.

• 터널과지하공간
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• 제5권2호
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• pp.95-103
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• 1995

In this paper the stress redistribution around tunnel face was analyzed by using a three-dimensional finite element model. The effects of in-situ stress levels, excavation sequences, stiffness difference between the hard ground and the weak zone on the stress redistributions were considered. Displacement and stress changes at tunnel crown, side wall, and invert were investigated throughout the sequential excavation. To show ground response, percentage of the displacement and stress variations are used as a function of normalized distance that is between the face and monitoring section. Preceding displacements and stress variations were presented to be adopted in the two-dimensional tunnel analysis.

• Geomechanics and Engineering
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• 제13권2호
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• pp.195-215
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• 2017

This paper proposes gob-side entry retaining by roof break and filling in thick-layer soft rock conditions based on the thick-layer soft rock roof strata migration law and the demand for non-pillar gob-side entry retaining projects. The functional expressions of main roof subsidence are derived for three break roof direction conditions: lateral deflection toward the roadway, lateral deflection toward the gob and vertically to the roof. These are derived according to the load-bearing boundary conditions of the main roadway roof stratum. It is concluded that the break roof angle is an important factor influencing the stability of gob-side entry retaining surrounding rock. This paper studies the stress distribution characteristics and plastic damage scope of gob-side entry retaining integrated coal seams, as well as the roof strata migration law and the supporting stability of caving structure filled on the break roof layer at the break roof angles of $-5^{\circ}$, $0^{\circ}$, $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$ are studied. The simulation results of numerical analysis indicate that, the stress concentration and plastic damage scope to the sides of gob-side entry retaining integrated coal at the break roof angle of $5^{\circ}$ are reduced and shearing stress concentration of the caving filling body has been eliminated. The disturbance of coal mining to the roadway roof and loss of carrying capacity are mitigated. Field tests have been carried out on air-return roadway 5203 with the break roof angle of $5^{\circ}$. The monitoring indicates that the break roof filling section and compaction section are located at 0-45 m and 45-75 m behind the working face, respectively. The section from 75-100 m tends to be stable.

• 지질공학
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• 제5권3호
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• pp.301-308
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• 1995

본 연구에서는 지하암반구조물의 해석시 재료특성변이를 확률론적으로 고려할 수 있는 수치해석기법을 제시하였다. 수치해석적 접근은 확률론적 해석분야에서 비교적 널리 사용 되어지고 있으며, 재료특성변수를 확률공간에서 분포특성과 분산형태에 따라 비교적 정확하게 추출할 수 있는 Monte Carlo 기법을 사용하였으며, 생성된 재료변수에 따른 변위와 응력의 계산과정은 유한요소법을 사용하였다.또한 본 연구 결과로부터 작성한 수치해석프로그램을 사용하여 2축응력장치에서의 지하원형암반공동에 대한 수치해석을 수행하였으며, 재료특성값의 분포특성변화에 따른 공동주변의 거동변화를 파악하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.163-170
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• 2001

This paper presents results of nonlinear analyses for underground structures including both the soil-structure interaction and nonlinear behavior of concrete material. For this purpose, a hybrid method is employed, in which a dynamic analysis technique for a linear soil-structure interaction system and a general purpose FE program are combined in hybrid and practical manners. A couple of nonlinear analyses are carried out for framed structures in multi-layered half space soil medium. The yielding of concrete structure is considered by a multi-linear stress- strain relationship. The numerical results suggest that ductile design fur the intermediate columns in the underground framed structure is substantially important in aseismic design.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.192-197
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• 2003

It can be said that rock mass properties are characterized not by a mean value but by values with variation due to its characteristic uncertainty. This characteristic is one of the most important parts for the design of underground structures, but yet to be fully examined. Stochastic finite element method (SFEM) has been developed in order to take the randomness of structural systems into account. Using SFEM, the response variability of structural system can be obtained and it leads probabilistic stability of structure to be analyzed. In this study, displacements response variability of circular opening with hydrostatic stress field are analyzed in terms of rock mass properties having a certain mean and a standard deviation using the SFEM. The analyzed response variability shows that the necessity of probabilistic stability analysis of underground structures using reliable mean value and standard deviation of deformation modulus.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.357-362
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• 2000

This Paper presents dynamic analysis of underground R/C Subway Structure, subjected to seismic actions. Earthquakes brought serious damage to RC subway Structure. Foe studying the collapse mechanism of underground RC Subway, seismic of a subway station is simulated in using FEM program ASP2000 of two-dimension based on the path dependent RC elastic model, soil foundation and interfacial models. The shear failure of intermediate vertical columns is founds to be the major cause of the structural collapse. According to FEM simulation of the failure mechanism, it is considered that the RC column would lose axial load carrying capacity after the occurrence of the localized diagonal shear cracks , and sudden failure of the outer frame would be followed. Specially, the shear stress in the middle slab reaches maximum shear capacity. So, the Structure would fail in the middle slab as a result of erasing the vertical ground motion computation.

• 한국건축시공학회지
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• 제6권4호
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• pp.45-52
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• 2006

Top Down method is more widely used in downtown construction, recently. As underground construction constitutes a significant portion of the total construction cost and time in Top Down construction, it is important to develop a construction method to reduce the time required in underground works. The purpose of this study is to analyze load carrying capacity of Top Down prefounded columns on different excavation schedule. When several floors are excavated, the valid buckling length of prefounded column is increased and allowable buckling stress is decreased. The result shows that all columns are safe in buckling down to B3 story whether 2 or 3 stories are excavated. However, several columns are not safe from B4 story when 2 or 3 stories are excavated straightly. With these results, a process can be designed that the first three stories in the basement are excavated, and then excavate B4 story after placing concrete on B1 and B2 floor.