• 한국안전학회지
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• 제31권2호
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• pp.57-63
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• 2016

Recently, subways in the city are formed a vast underground network which is interfered with construction when large-scale infrastructure will be planned to nearby existing subway tunnels. Researches have been restricted to estimate stability of existing subway tunnel due to adjacent excavation causued by small construction such as buildings. In this paper, OO underpass is planned on the top of existing subway tunnel, which will be need large-scale excavation, is selected as a subject of study. And the purpose of this study is to analyze the effects on existing subway tunnel due to excavation by stages on construction of underpass. The 3D-numerical analysis was performed by using the MIDAS/GTS program. The stability on existing subway tunnel caused by sequential excavation is analysed using numerical results. Based on the analysis, the excavation orders and reinforcement methods was suggested for stability of exiting subway tunnel.

• 한국측량학회지
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• 제30권6_2호
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• pp.623-629
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• 2012

During the construction of crossing engineering one of the important measures to ensure the safety of subway operation is the implementation of deformation surveying to the existing subway tunnel. Guangzhou new subway line 2 engineering which crosses the existing tunnel is taken as the background. How to achieve intelligent and automatic deformation surveying forecast during the subway tunnel construction process is studied. Because large amount of surveying data exists in the subway construction, deformation analysis is difficult and prediction has low accuracy, a subway intelligent deformation prediction model based on the PBIL and support vector machine is proposed. The PBIL algorithm is used to optimize the exact key parameters combination of support vector machine though probability analysis and thereby the predictive ability of the model deformation is greatly improved. Through applications on the Guangzhou subway across deformation surveying deformation engineering the prediction method's predictive ability has high accuracy and the method has high practicality. It can support effective solution to the implementation of the comprehensive and accurate surveying and early warning under subway operation conditions with the environmental interference and complex deformation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 지하공간 건설기술에 관한 서울 심포지움 논문집
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• pp.3-30
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• 1993

To ease traffic congestion Seoul Metropolitan Government formulated the 2nd Phase of Seoul Subway Construction Scheme in 1989. The scheme calls for the construction of %60 km of subway which includes addition of 4 more subway lines and extension of 3 existing subway lines in addition to the existing 118 km of subway. As a final stage of the scheme subway line 6 is under planning and design. The line 6 is 36.1 km-long route connecting Ungam-Samgakchi-Changsin-Sinnae. Except for the depot main line wilts be underground and major construction methods are cut and cover and tunnelling. As a tunnelling method New Austrian Tunnelling Method will be adapted. The line will be opened by the end of 1997. With the completion of the line Seoul will have 278 km of subway network and the transport share by subway will be increased from 25% in 1992 to 50% in 1997.

• 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.25-34
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• 1990

For the construction of twin single track subway tunnels by NATM within close proximity of existing vehicle underpass in the highly congested area of downtown Seoul, finite element analyses were performed to evaluate the ground responses during tunnelling and also the stability and safety of the underpass structure and subway tunnels. Results of the analyses indicated the need to improve the soil beneath the underpass, and pre-grouting was carried out prior to the tunnel excavation. During tunnel construction field measurement program was implemented to confirm the results of anslyses and to control the tunnel construction procedures, thus ensuring stability of the existing structres.

• International Journal of Railway
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• 제9권1호
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• pp.21-26
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• 2016

When excavation under existing structure is planned for a new construction project, the underpinning method is one of the most applicable construction methods. This study introduces a new modified underpinning method which is applied to construct a new subway line in Seoul Metropolitan. The new subway line was designed to pass underneath the existing subway line. Existing subway line carries about 2 million passengers daily, which is 33% of total passengers using subway in Seoul, and is the only circulation line in Seoul. Subway trains are passing 540 times through this section in a day. By applying a new underpinning method, the subway box structure of line is exposed 54m in the air supported by bearing piles. The proposed method was carefully monitored using heavy instrumentation system during construction. This study proposed and verified the application of the modified underpinning method, which can reduce construction period by 1.5 times and the construction cost by 1.2 times comparing with conventional method. The importance of considering construction sequence is investigated and verified by analyzed data non-considering construction sequence. The unexpected heaving which can bring up a dangerous situation for train running stability were measured, so this study shows that the upward movement has to be analyzed in designing process. As the use of underground space increases, the proposed method can be a good example of underground development.

• 수산해양교육연구
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• 제21권2호
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• pp.269-277
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• 2009

Ventilation equipment performs a central role to maintain comfort subway environment. So ventilation equipment of Busan subway line No.1 is required to improve thermal environment. In this study, conditions of thermal environment are presented to improve ventilation equipment at existing subway station platforms by measuring thermal environment of platforms operated ventilation equipment at 14 stations of Busan subway line No.1. AWS of data in comparison with the neighbouring platforms and thermal environment analysis. Thermal environment status of subway platform analysis results are as follows. 1)Daytime platform temperature was higher than outdoor temperature, but night time platform temperature was lower than outdoor temperature. 2)Train wind had effect on improving thermal comfort in platform. 3)When outdoor temperature is below $24^{\circ}C$, inlet air is able to lower than platform temperature. 4)Considering existing ventilation system, night purge systems is useful to improving platform thermal environment.

• 한국지반환경공학회 논문집
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• 제15권10호
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• pp.23-28
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• 2014

최근 도심재개발사업의 증가로 기존 건물 철거 후 신축공사를 하는 사례가 증가하는 추세이다. 그러나 현재까지의 연구는 신축공사에 따른 인접굴착이 지하철 터널에 미치는 영향 검토에 국한되어 왔다. 이에 따라 기존 주차장 건물을 철거한 후 신축공사가 이루어지는 ${\bigcirc}{\bigcirc}$건물 신축사업을 연구대상으로 선정하여 상부 건물 철거 등으로 인한 하중제하 및 하중재하에 따른 지하철 터널에 미치는 영향 검토를 수행하였다. 수치해석은 기존 건물 철거를 고려한 경우와 고려하지 않은 경우에 대해 MIDAS/GTS를 사용하여 3차원 수치해석을 수행하고 터널 변위 및 부재력 결과 분석을 통해 기존 건물 철거가 지하철 터널에 미치는 영향을 검토하였다. 그 결과 기존 건물 철거를 고려하는 경우가 고려하지 않는 경우보다 지하철 터널에 미치는 영향이 더 큰 것으로 나타났다.

• 한국터널지하공간학회 논문집
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• 제22권1호
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• pp.59-76
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• 2020

지속적인 수도권 교통 인프라 수요의 증가에 따른 광역·도시철도 노선의 급행화를 위해서는 완행과 급행철도를 동시에 운영할 수 있도록 하는 부본선의 건설이 요구된다. 그러나 기존 지하철 노선의 운행을 중단한 후 부본선을 건설하는 것은 많은 경제적 손실을 발생시키므로 기존 지하철 터널의 운영 중 확폭 방안에 대한 연구가 필수적이다. 따라서 본 논문에서는 기존 노선 급행화에 필요한 부본선 건설을 위해 기존 지하철 터널의 운영 중 확폭 방안에 대한 기초연구를 수행하였다. 기존선 운영 중 부본선 건설방안 모색을 위해 지하철 4호선 과천선의 정부과천청사역을 부본선 건설 가상 역사로 선정하고, 4가지 방안의 구간별 단면 및 공법계획을 검토하였으며, 해당 역사에 대하여 부본선을 시공하였을 경우 시공성·경제성에 비해 상대적으로 안정성이 우려된다고 판단되는 방안을 선정하여 부본선 시공과정을 고려한 3차원 수치해석을 통한 안정성 검토를 수행하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.1064-1072
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• 2005

Since July 1st of 2004, a transit fare system of Seoul metropolitan area has been changed. The distinguished characteristics of the system can be described as two issues that can be summarized by distance based fare for Seoul metropolitan area and fare discount between bus and transit in Seoul city area. In Seoul city area, some existing subway users, however, complained the raised fare compared to previous fare system. An alternative, season ticket was introduced by Seoul local government in July 15th of 2004. Due to the ticket, even though periodic subway users could reduce average subway costs, the benefit of the season ticket was very limited to subway users in Seoul city area. Therefore, this study proposes a methodology to enlarge the benefit of the existing season ticket in Seoul metropolitan area.

• Geomechanics and Engineering
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• 제35권5호
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• pp.525-538
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• 2023

The development of a city is closely linked to the construction and operation of its subway system. However, constructing a new subway tunnel under an existing station is an extremely complex task, and the deformation characteristics and mechanical behavior of the new subway tunnel during the excavation process can greatly impact the normal operation of the existing station. Although the previous studies about the case of underpass engineering have been carried out, there is limited research on the condition of a newly-built subway tunnel that closely undercrossing an existing station with zero distance between them. Therefore, this study analyzes the deformation law and mechanical behavior characteristics of the preliminary lining of the underpass tunnel during the excavation process based on the real engineering case of Chengdu Metro Line 8. This study also makes an in-depth comparison of the influence of different excavation methods on this issue. Finally, the accuracy of numerical simulation is verified by comparing it with on-site result. The results indicate that the maximum bending moment mainly occurs at the floor slab of the preliminary lining, while that of the ceiling is small. The stress state at the ceiling position is less affected by the construction process of the pilot tunnel. Compared to the all-in-one excavation method, although the process of partial excavation method is more complicated, the deformation of preliminary lining caused by it is basically less than the upper limit value of the standard, while that of the all-in-one excavation method is beyond standard requirements.