• Geomechanics and Engineering
• /
• 제22권6호
• /
• pp.497-507
• /
• 2020

This paper presents the results of a three-dimensional numerical investigation into the effect of new tunnel construction on structural performance of existing tunnel lining. A three-dimensional finite difference model, capable of modelling the tunnel construction process, was adopted to perform a parametric study on the spatial variation of new tunnel location with respect to the existing tunnel with emphasis on the plan crossing angle of the new tunnel with respect to the existing tunnel and the vertical elevation of the new tunnel with respect to the existing one. The results of the analyses were arranged so that the effect of new tunnel construction on the lining member forces and stresses of the existing tunnel can be identified. The results indicate that when a new tunnel underpasses an existing tunnel, the new tunnel construction imposes greater impact on the existing tunnel lining when the two tunnels cross at an acute angle. Also shown are that the critical plan crossing angle of the new tunnel that would impose greater impact on the existing tunnel depends on the relative vertical location of the new tunnel with respect to the existing one, and that the overpassing new tunnel construction scenario is more critical than the underpassing scenario in view of the existing tunnel lining stability. Practical implications of the findings are discussed.

• 한국작물학회지
• /
• 제31권1호
• /
• pp.84-90
• /
• 1986

단옥수수 품종 Great Bell을 3월 5일, 15일, 25일과 4월 4일에 파종하고, 파종기마다 투명 P.E. 필름의 Tunnel, Tunnel slit 및 Mulch가 기온, 지온 및 단옥수수의 생육과 수량에 미치는 영향은 다음과 같다. 1. 최고최저기온과 최고최저지온 모두 Tunnel>Tunnel slit> Mulch의 순으로 높았으며 P.E. 필름 처리간 온도차이는 최고기온 및 지온은 컸으나 최저기온 및 지온은 적었다. 2. 4월 하경에 Tunnel내 기온이 4$0^{\circ}C$가 넘어 필름을 열면 Tunnel구의 기온은 Mulch에서와 같으나 지온은 낮았다. Tunnel slit는 필름을 열지 않고 slit수를 증가시켜 고온장해를 피할 수 있었다. 3. 옥수수 유묘기의 저온피해는 Mulch에서는 지상부가 고사하였으나 재생되었고, Tunnel slit에서는 잎의 일부가 피해를 입었으나 Tunnel에서는 피해가없었다. 4. 3월 5일 및 15일 파종에서 Tunnel은 Tunnel slit나 Mulch보다 초기생육과 출사를 촉진시켰으나 고온으로 낮에 필름을 열었던 3월 25일 및 4월 4일 파종에서는 오히 려 지연시켰다. 5. 파종이 늦을수록 파종에서 출사까지 일수가 단축되어 3월 25일 파종에 비하여 3월 5일 및 15일 파종은 출사가 2~3일 빨랐으며 4월 4일 파종은 6~9일 늦었다. 6. 적조위축병은 한기파종에서 이병율이 높았으며, 3월 25 일 및 4월 4 일 파종의 Tunnel slit에서는 생육초기에 필름을 열지 않아 적조위축병 이병율이 Tunnel 이나 Mulch보다 낮았다. 7. 상품성 있는 웅수수는 적조위축병이 심했던 3월 5일 파종의 Mulch를 제외하면 모든 처리간에 차이가 없었다. 조수입은 상품가치가 큰 웅수가 많았던 3월 25일 파종의 Tunnel 및 Tunnel slit와 가격이 높고 웅수가 많았던 3월 5 일 파종의 Tunnel과 Tunnel slit에서 높았다.

• Geomechanics and Engineering
• /
• 제31권3호
• /
• pp.237-248
• /
• 2022

Nowadays, more and more subway tunnels were planed and constructed underneath the ground of urban cities to relieve the congested traffic. Potential damage may occur in existing tunnel if the new tunnel is constructed too close. So far, previous studies mainly focused on the tunnel-tunnel interactions with circular shape. The difference between circular and horseshoe shaped tunnel in terms of deformation mechanism is not fully investigated. In this study, three-dimensional numerical parametric studies were carried out to explore the effect of different tunnel shapes on the complicated tunnel-tunnel interaction problem. Parameters considered include volume loss, tunnel stiffness and relative density. It is found that the value of volume loss play the most important role in the multi-tunnel interactions. For a typical condition in this study, the maximum invert settlement and gradient along longitudinal direction of horseshoe shaped tunnel was 50% and 96% larger than those in circular case, respectively. This is because of the larger vertical soil displacement underneath existing tunnel. Due to the discontinuous hoop axial stress in horseshoe shaped tunnel, significant shear stress was mobilized around the axillary angles. This resulted in substantial bending moment at the bottom plate and side walls of horseshoe shaped tunnel. Consequently, vertical elongation and horizontal compression in circular existing tunnel were 45% and 33% smaller than those in horseshoe case (at monitored section X/D = 0), which in latter case was mainly attributed to the bending induced deflection. The radial deformation stiffness of circular tunnel is more sensitive to the Young's modulus compared with horseshoe shaped tunnel. This is because of that circular tunnel resisted the radial deformation mainly by its hoop axial stress while horseshoe shaped tunnel do so mainly by its flexural rigidity. In addition, the reduction of soil stiffness beneath the circular tunnel was larger than that in horseshoe shaped tunnel at each level of relative density, indicating that large portion of tunneling effect were undertaken by the ground itself in circular tunnel case.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.835-844
• /
• 2009

In this study, a database composed by 46 cases of tunnel collapses has been built up. Based on the database, comprehensive data analysis is carried out, providing us a number of the technical lessons, which can be considered in future design and construction to minimize possibility of tunnel collapse disaster. For making a better understanding, the technical lessons are given in two divisions: mountain tunnel and urban tunnel. Tunnel collapses taking place in the former tunnel are generally due to bad discontinuity condition of jointed rock mass. Otherwise, urban tunnel has weak condition generally on ground water and weathering of ground. Most of technical comments given in this paper are made based on the cases of tunnel collapses only used in this study, so that the comments seems to be hard to be available to all the tunnelling cases. However, the comment should be valuable technical lessons for tunnel engineers to consider in tunnel design or construction.

• 한국터널지하공간학회 논문집
• /
• 제8권4호
• /
• pp.307-324
• /
• 2006

본 논문에서는 운영중인 터널에 인접하여 신설터널이 시공되는 경우 터널간 상대적인 위치관계에 따른 기존터널의 라이닝에 미치는 영향에 대한 내용을 다루었다. 신설터널이 인접하여 시공되는 조건에 대해2차원 및 3차원 유한요소해석을 통해 매개변수 연구를 수행하여, 신설터널의 상대적 위치 및 굴진에 따른 기존터널 라이닝의 유발된 단면력과 변형형상의 변화경향을 분석하였다. 신설터널은 기존터널의 상부 또는 하부에 시공되는 경우 그 영향이 가장 크게 작용하는 것으로 나타났으며 측벽방향으로 수평하게 시공되는 조건이 가장 안정적으로 분석 되었다. 한편 기존터널과 교차하여 시공되는 경우 기존터널의 상부보다 하부에 신설터널이 시공될 때의 영향이 더 큰 것으로 나타났다.

• 한국도로학회논문집
• /
• 제18권2호
• /
• pp.19-27
• /
• 2016

PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.101-108
• /
• 2000

In this study, an expert system was developed to predict the safety of tunnel and choose proper tunnel reinforcement system using fuzzy quantification theory and fuzzy inference rule based on tunnel information database. The expert system developed in this study have two main parts named pre-module and post-module. Pre-module decides tunnel information imput items based on the tunnel face mapping information which can be easily obtained in-situ site. Then, using fuzzy quantification theory II, fuzzy membership function is composed and tunnel safety level is inferred through this membership function. The comparison result between the predicted reinforcement system level and measured ones was very similar. In-situ data were obtained in three tunnel sites including subway tunnel under Han river, This system will be very helpful to make the most of in-situ data and suggest proper applicability of tunnel reinforcement system developing more resonable tunnel support method from dependance of some experienced experts for the absent of guide.

• 한국안전학회지
• /
• 제20권3호
• /
• pp.112-119
• /
• 2005

In road tunnel, in order to prevents an accident and minimize the damage of an accident in the case of fire, safety facilities and equipments are integral parts. The type and amount of safety facilities are based on tunnel type and length, traffic flow rate, etc. Therefore many countries use a tunnel classification system that categories tunnel into groups, and specifies the necessary emergency equipment for each group. In this study, for the purpose of classifying tunnel based on tunnel ist investigated the domestic and foreign standards and regulations for safety of road tunnel. As a results, we suggest the method of classification of tunnel by traffic performance, tunnel grade, the volume of traffic, fraction of HGV, rules or regulations for transports of dangerous good through tunnel.

• 한국지반공학회논문집
• /
• 제18권5호
• /
• pp.221-228
• /
• 2002

터널 굴착시 막장의 안정성은 주변지반 및 터널 지보재의 안정성과 아울러 가장 중요하게 평가되어야 할 요소 중의 하나이다. 특히 터널이 지하수위 하에서 시공될 경우 지하수 흐름에 따라 터널 막장에서 발생하게 되는 침투력은 터널 막장의 안정성에 심각한 영향을 미칠 수 있다. 따라서 본 침투력은 터널 설계 및 시공시 터널 막장의 안정성 측면에서 중요하게 평가되어야 할 요소이다. 본 연구에서는 지하수위 하에서 터널이 시공될 경우 발생하는 침투력과 관련하여 터널 굴진율이 본 칩투력에 미치는 영향에 대해서 언급하였다. 터널 굴진율을 고려한 지하수 흐름해석을 위하여 유한요소 해석 프로그램이 개발되었다. 본 프로그램을 이용하여 터널 굴진율 및 지반의 투수특성이 터널 막장에 작용하는 침투력에 미치는 영향을 매개변수 분석을 통하여 연구하였다. 본 연구결과, 터널 굴진율은 터널 막장에 작용하는 침투력을 평가하는데 있어서 중요한 추가된 요소로 고려되어야 하며, 결론적으로 터널 막장의 안정성을 유지하기 위한 지보압의 합리적인 산정을 위한 방법론을 제시할 수 있었다.

• 소음진동
• /
• 제7권6호
• /
• pp.959-966
• /
• 1997

In general, the booming noise intensity at tunnel exit is strongly related to the gradient of the compression wave front created by high speed train entering the tunnel. This paper presents some results in relation with the compression wave front produced when the high speed train enters a tunnel. Four kinds of tunnel entrance shape with real dimensions were studied to investigate the formation of compression wave front inside tunnel by train entering tunnel. Computations were carried out using three-dimensional compressible Euler equation with vanishing viscosity and conductivity of fluid. According to the results, the flow disturbances occured at tunnel entrance were eliminated by tunnel hood with same cross sectional area. The compression wave front is formed completely at 30-40m from tunnel entrance. The maximum pressure gradient of compression wave front is reduced by 29.8% for the inclined tunnel hood and reduced by 21.5% for the tunnel hood with holes at the top face with tunnel without hood. The length of the inclined hood is 15m and the length of the hood with holes is 20m.