• Geomechanics and Engineering
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• 제20권2호
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• pp.103-112
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• 2020

The dynamic response of crossing tunnels under heavy-haul train loads is still not fully understood. In this study, based on the case of a high-speed tunnel underneath an existing heavy-haul railway tunnel, a model experiment was performed to research the dynamic response characteristics of crossing tunnels. It is found that the under-crossing changes the dynamic response of the existing tunnel and surrounding rock. The acceleration response of the existing tunnel enhances, and the dynamic stress of rock mass between crossing tunnels decreases after the excavation. Both tunneling and the excitation of heavy-haul train loads stretch the tunnel base, and the maximum tensile strain is 18.35 µε in this model test. Then, the measured results were validated by numerical simulation. Also, a parametric study was performed to discuss the influence of the relative position between crossing tunnels and the advanced support on the dynamic behavior of the existing tunnel, where an amplifying coefficient of tunnel vibration was introduced to describe the change in acceleration due to tunneling. These results reveal the dynamic amplifying phenomenon of the existing tunnel during the new tunnel construction, which can be referred in the dynamic design of crossing tunnels.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2008년도 국제학술회의
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• pp.33-41
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• 2008

The longest tunnel has been halted at Daekwanryung by the failure of the host country of the Winter Olympiad in 2014, but modern High-Power TBM will come to Korea to excavate these long tunnels to establish the better horizontal connection between the western and eastern countries to improve the strong powerful logistic strategy of Korean peninsula. Train operation provides a key function of air movements in a long underground tunnel, and heat generation from transit vehicles may account of the most heat release to the ventilation and emergency systems. This paper indicates the optimal fire suppress services and safety provision for the long railway tunnel which is designed twin tunnel with length 22km in Gangwon province of Korea. The design of the fire-fighting systems and emergency were prepared by the operation of the famous long-railway tunnels as well as the severe lessons from the real fires in domestic and overseas experiences. Designers should concentrate the optimal solution for passenger's safety at the emergency state when tunnel fires, train crush accidents, derailment, and etc. The optimal fire-extinguishing facilities for long railway tunnels are presented for better safety of the comfortable operation in this hard rock tunnel of eastern mountains side of Korea. Since year 1900, hard rock tunnel construction has been launched for railway tunnels in Korea, tunnels have been built for various purposes not only for infrastructure tunnels including roadway, railway, subway, and but also for water and power supply, for deposit food, waste, and oils etc. Most favorable railway tunnel system was discussed in details; twin tunnels, distance of cross passage, ventilation systems, for the comfortable train operations in the future.

• 자연, 터널 그리고 지하공간
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• 제3권2호
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• pp.32-44
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• 2001

Most of the major aspects of the high speed rail tunnels in Korea, including such items as the tunnel geometry, excavation methods, primary support, final lining, drainage and waterproofing, are similar to the practices followed in other countries. The tunnels in Korea provide the largest net internal area $(107\;m^2)$ as compared to the other counties addressed in this paper. The effective adaptation and modification of international practices and designs, combined with the integration of domestic practices, has resulted in the successful construction of these large tunnels. The experience gained from the completed work to date on the high speed line in Korea, combined with international technology input, will help to ensure future tunnels are constructed in an efficient manner with adequate design measures implemented for the long-term operational life of the tunnels. As has occurred in these other countries, further improvements and modifications to the Korea high-speed railway tunnels will occur as experience is gained and new technology develops.

• Geomechanics and Engineering
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• 제28권3호
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• pp.225-237
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• 2022

Settlement evaluation is important for shallow tunnels in big cities to estimate the settlement that occurs due to the excavation of twin tunnels. The majority of earlier research on analytical solutions, on the other hand, concentrated on calculating the settlement for a single tunnel. This research introduces a procedure to evaluate the settlement induced by the excavation of twin tunnels (two parallel tunnels). In this study, a series of numerical analysis were performed to validate the analytical solution results. Two geological conditions were considered to derive the settlement depending on each case. The analytical and numerical methods were compared, which involved considering many sections and conducting a parametric study; the results have good agreement. Moreover, a comparison of the 3D flat model and 2D (FEM) with the analytical solution shows that in the fill soil, the maximum settlement values were obtained by the analytical solution. In contrast, the values obtained by the analytical solution in the rock is more conservative than those in the fill. Finally, this method was shown to be appropriate for twin tunnels dug side by side by utilizing finite element analysis 3D and 2D (PLAXIS 3D and PLAXIS 2D) to verify the analytical equations. Eventually, it will be possible to use this approach to predict settlement troughs over twin tunnels.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지하공간 건설기술에 관한 서울 심포지움 논문집
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• pp.51-76
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• 1993

More than sixty percentages of tunnels in the second phase of Seoul subway project have the ground coverages less than twenty meters. Majority of ground conditions encountered during turutel ling, therefore, are weathered rocks or weathered scils. Substantial lengths of tunnels are being constructed and designed running through the alluvial deposits as well. A comprehensive evaluation of current design and construction technology of Seoul subway tunnels is made with four categories such as site investigations, design concepts and methods, auxiliary measures and quality controls. Critical comments are given and some suggestions for the improvement of technology are presented.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.633-639
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• 2005

We studied three dimension numerical analysis in the case that a train stops in tunnels by fire. And the 'Fluent 6.1' which is CFD(Computational Fluid Dynamics) program was used in this study. We compare the smog diffusion in single/double track ordinary railway tunnels with that in double track high speed railway tunnels in this study.

• Geomechanics and Engineering
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• 제12권3호
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• pp.361-397
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• 2017

The unloading effect from excavations can cause the deformation of adjacent tunnels, which may seriously influence the operation and safety of those tunnels. However, systematic studies of the deformation characteristics of tunnels located along side excavations are limited, and simplified methods to predict the influence of excavations on tunnels are also rare. In this study, the simulation capability of a finite element method (FEM) considering the small-strain characteristics of soil was verified using a case study. Then, a large number of FEM simulations examining the influence of excavations on adjacent tunnels were conducted. Based on the simulation results, the deformation characteristics of tunnels at different positions and under four deformation modes of the retaining structure were analyzed. The results indicate that the deformation mode of the retaining structure has a significant influence on the deformation of certain tunnels. When the deformation magnitudes of the retaining structures are the same, the influence degree of the excavation on the tunnel increased in this order: from cantilever type to convex type to composite type to kick-in type. In practical projects, the deformation mode of the retaining structure should be optimized according to the tunnel position, and kick-in deformation should be avoided. Furthermore, two methods to predict the influence of excavations on adjacent tunnels are proposed. Design charts, in terms of normalized tunnel deformation contours, can be used to quantitatively estimate the tunnel deformation. The design table of the excavation influence zones can be applied to determine which influence zone the tunnel is located in.

• 한국터널지하공간학회 논문집
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• 제15권2호
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• pp.69-80
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• 2013

본 연구에서는 터널에 대한 내진설계 기준이 처음으로 제정된 1999년 이전에 설계된 현재 운영중인 도로 터널의 지진에 대한 성능을 평가하였다. 이를 위하여 1999년 이전에 설계된 도로 터널 자료를 조사하였으며 이중에서 가장 지진에 취약할 것으로 예상되는 대표 단면을 선정하여 이들에 대한 정밀한 안전성 평가를 수행하였다. 사용된 해석방법은 응답변위법과 동적해석이며 모두 유한차분해석 프로그램을 이용하였다. 응답변위법은 전체영역과 축소된 해석 영역에 대한 해석을 수행하였으며 동적해석은 비선형 해석을 수행하였다. 해석 결과, 축소된 해석영역에 대한 응답변위법과 동적해석의 결과가 매우 유사한 것으로 나타났으며 내진설계가 적용되지 않은 터널들도 재현주기 1000년 지진에 대해서는 안전하며 추가적인 보강은 불필요한 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1990년도 PROCEEDINGS OF THE FIRST KOREA-JAPAN JOINT GEOTECHNICAL SEMINAR ON EXCAVATION and TUNNELING IN URBAN AREAS
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• pp.69-86
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• 1990

This paper discusses how to protect the principal structures adjacent to subway tunnels being constructed by the shield or cut-and-cover methods by referring to some actual examples.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.252-254
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• 2003

In this study, it was purposed to develop the new method for the prediction of pollutant concentration in road tunnels. The new method was the use of artificial neural network with the back-propagation algorithm which can model the non-linear system of tunnel environment. This network system was separated into two parts as the visibility and the CO concentration. For this study, data was collected from two highway road tunnels on Yeongdong Expressway. The tunnels have two lanes with one-way direction and adopt the longitudinal ventilation system. The actually measured data from the tunnels was used to develop the neural network system for the prediction of pollutant concentration. The output results from the newly developed neural network system were analysed and compared with the calculated values by PIARC method. Results showed that the prediction accuracy by the neural network system was approximately five times better than the one by PIARC method. ill addition, the system predicted much more accurately at the situation where the drivers have to be stayed for a while in tunnels caused by the low velocity of vehicles.