• Journal of Korean Society of Disaster and Security
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• v.12 no.4
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• pp.43-52
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• 2019

To analyze the influence on the stability, resulting from application of upgrade pipe roof structure (UPRS) method to the structure existed under subway Station, physical properties of a ground, elasticity and elasto-plastic theories, including displacement analysis of finite elements, stress analysis of finite elements, displacement caused by steel pipe propulsion and internal excavation, and stress change in a steel pipe, were introduced. Then, the influence on structural stability when applying the UPRS method was compared and reviewed based on the construction management standard of the Ministry Land, Infrastructure and Transport and foreign sources, using numerical analysis with a model which assumes that each microelement divided into a structurally stable point consists of the connection of finite points. As a result of the finite element analysis, 7.21 mm maximum displacement, 1/3,950 angular displacement, 70.28 MPa bending compressive stress of steel pipe structure constructed with UPRS (non-excavation) method and 477.38 MPa maximum shear strength were within their allowable standards (25.00 mm, 1/500, 210.00 MPa and 120.00 MPa, respectively), and therefore, the results showed that the design and construction are stable.

• Geotechnical Engineering
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• v.11 no.1
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• pp.63-78
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• 1995

Recently, in order to utilize more effectively underground space, deep excavations have been performed on building or subway construction in urban areas. In such excavations, anchors have been used to support the excavation retaining walls because the anchored excavation could provide wide working space for underground construction. The purpose of this paper is to establish empirical equations to be able to estimate the earth pressures acting on anchored excavation retention walls, based on the investigation of field measuring results, which were obtained from twenty seven building construction sites. The prestressed anchor force was measured by load cells which were attached to the anchor head, while the horizontal displacement of excavation walls were measured by inclinometers which were installed right'behind the retention walls. The lateral earth pressures acting on the anchored retention walls, which were estimated from both the measured anchor forces and the horizontal displacement of the walls, showed a trapezoidal distribution. There was some difference between the measured earth pressures acting on the anchored retention walls and the empirical earth pressures given by several empirical equations. Thus, the lateral earth pressures acting on anchored retention walls would be estimated by these empirical equations with some modifications.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.37-44
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• 2010

Recently, urban retrofit and extension, development of new buildings and facilities, and construction of underground structures like subway tunnels in urban areas give rise to significance of site investigation at urban areas. However, ambient electric noises, traffic vibrations, embedded objects work as obstacles to high-quality and accuracy in site investigation at urban areas. In this paper, a new technique called the pseudo-DC resistivity survey (in brief, PDC-R) was proposed to minimize the adverse effect of ambient electrical noises in resistivity survey. PDC-R technique utilizes an AC current with frequency range of 0.1 to 1.0 Hz rather than DC current, which is used for conventional resistivity survey. The motivation of using low-frequency AC current is to avoid 60-Hz components or its multiples in the resistivity survey which ambient noises are mostly composed of. The implementation of PDC-R technique also included the parametric study on skin effect, frequency effect and current-level effect, which led to the determination of optimal values of frequency and current level for PDC-R survey. The reliability and feasibility of PDC-R technique was verified through field tests, accompanied by the comparison with DC resistivity survey and CapSASW tests.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.395-400
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• 2007

LRT(Light Railway Train), which is a intermediate system of train and bus, is arose for the solution of subway construction cost and the transportation capacity of bus. LRT was introduced in 1980's. About 30 local governments are plan to introduce LRT or constructing LRT, at present. AGT(Automated Guide-way Transit) system, which is a kind of LRT, is operated without driver. Rubber wheeled AGT system can reduce the noise and vibration compare to steel wheeled AGT, so it is estimated as ideal transportation system for urban area. And live loads at bridge are classified as the static load of vehicle and the dynamic wheel contact load which is occurred from the interaction of bridge and vehicle vibration, and the surface roughness. In the case of AGT system, the dynamic increment factor of bridge is greater than the normal train bridge and roadway bridge, because, the weight of AGT vehicle is more light that the train of truck. The exact method for dynamic increment factor is experiment. But this method is needed much money and time, moreover, this method cannot be adopted in design. Therefore, a simulation program for the interaction of AGT bridge, vehicle and surface roughness was developed, in this study. And the program was verified by experiment. As a result, the accuracy of the simulation program can be verified.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.115-119
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• 2002

Four tunnels have been planned to operate a large diameter shielded TBM in Gwangju urban subway construction site. No.1 tunnel has completely been excavated for 13 months operating. Net penetration rate and its relations with thrust farce of the shielded TBM are analysis in this report. This shallow depth tunnel of 536m length is located in soil layers at launching and in hard rocks at ending with 84 m length. The weekly net penetration rates haute dropped down as low as 20∼110 mm/hr in rock while 400∼800 mm/hr in soil. The actual penetration rates we proved to be high as the theoretical penetration rate which is analysis in consideration of conditions of machine and rock. And net penetration rate is investigated to increase linearly thrust force.

• Journal of Urban Science
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• v.6 no.2
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• pp.29-34
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• 2017

Although the supply of public parking lots in major cities is steadily increasing, there is still a shortage of parking spaces that take into account the characteristics of actual available parking spaces. These parking problems are caused by conflicts between users, illegal occupation and privatization of roads, interference with traffic roads, and business stagnation in commercial areas and illegal parking problems. In addition, despite various parking demand management policies and continuous supply of public parking facilities, the solution to the parking problem is uneasy due to increased construction costs and changes in social conditions. In order to solve this problem, it was judged that it would be necessary to utilize the existing public parking lots efficiently. Therefore, we collect the variables expected to affect the turnover, and use multiple regression models. The results are summarized as follows. Firstly, public parking lots can be classified into four types using utilization rate and turnover rate. Secondly, influencing factors are found including index of public transportation usage convenience, index of illegal parking, and land use characteristics in central commercial district. Thirdly, it was shown that there was little impact by the size of public parking lots, separation distance to subway distance, separation distance to bus stops, transfer zone, residential zone, and second-rated lots by parking costs. Finally, it is found that public parking lots can be improved by proving accessibility of public transit, enforcement of illegal parking, active approaches supporting public parking lots. It is also recommended that public parking cost rating system based mainly on land use characteristics should be remedied and rearranged.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.565-570
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• 2024

Recently, due to adjacent excavation work such as new buildings and common tunnel expansion concentrated around the urban railway, deformation of the underground box and tunnel structure of the urban railway built underground has occurred, and as a result, repair and reinforcement work is frequently carried. In addition, the subway is responsible for large-scale transportation, so ensuring the safety and drivability of underground structures is very important. Accordingly, an automated measurement system is being introduced to manage the safety of underground box structures. However, there is no analysis of structural damage vulnerabilities caused by subsidence or uplift of underground box structures. In this study, we aim to analyze damage vulnerabilities for safety monitoring of underground box structures. In addition, we intend to analyze major core monitoring locations by modeling underground box structures through numerical analysis. Therefore, we would like to suggest sensor installation locations and damage vulnerable areas for safety monitoring of underground box structures in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.45-51
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• 2010

In urban area, design and construction of civil engineering structures such as subway tunnel, underground space and deep excavation is impeded by unreliable site investigation. Variety of embedded objects, electric noises and traffic vibrations degrades the quality of site investigation, whatever the site-investigation technique would be. In this research, a preliminary research was performed to develop a dedicated site investigation technique for urban geotechnical sites, which can overcome the limitations of urban sites. HiRAS (Hybrid Integration of Surface Waves and Resistivity) technique which is the first outcome of the preliminary research was proposed in this paper. The technique combines surface wave as well as electrical resistivity. CapSASW method for surface-wave technique and PDC-R technique for electrical resistivity survey were incorporated to develop HiRAS technique. CapSASW method is a good method for evaluating material stiffness and PDC-R technique is a reliable method for determination of underground stratification even in a site with electrical noise. For the inversion analysis of HiRAS techniuqe, a site-specific relationship between stress-wave velocity and resistivity was employed. As for outgrowth of this research, the 2-D distribution of Poisson's ratio could be also determined.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.215-222
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• 2003

Recently the deep and large excavations are performed near the existing buildings in urban areas for the practical use of underground space. The earth pressure due to the excavation are varied according to the conditions of ground, the depth of excavation, the construction methods, and the method of supporting the earth pressure etc.. In this study, not only the behavior of axial load and distribution of earth pressure on the flexible wall according to stage excavation depth but also magnitude and distribution of lateral deformation, and the equivalent earth pressure from strut axial loads were analyzed by the results measured from instruments such as, load cells, strain gauges, and in-situ inclinometer, on the field of subway construction. According to the results of this study in the case of stage excavation the earth pressure of soft clayey soil is compounded with Terzaghi-Peck and Tschebotarioff.

• Journal of Korean Society of Transportation
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• v.23 no.5 s.83
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• pp.157-167
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• 2005

Seoul metropolitan public transport reform results in the introduction of the semi-public operation and distance-based fare policies. With implementation of these policies, public transport revenue allocation has been (will be) evolved very complicated because the existing revenue allocation issues have not only been clearly solved, which is generated by the combined relationship among Korea Railroad Corporation (KRC). Seoul Metropolitan Subway Corporation (SMSC). Seoul Metropolitan Rapid Transit Corporation (SMRTC), and Incheon Rapid Transit Corporation (IRTC), but also the revenue allocation problem between bus and urban railroad-related organizations need to be considered in this combined framework. On top of that. based on the future plans such as the private sector's railroad construction plan(s), the light rail transit construction plans of several local governments and the join of remained bus lines of Seoul metropolitan areas, it is understood that the revenue allocation among public transport operating organization will become one of main issues of operation organization as well as local and central governments. As a basic approach for revenue allocation of public transport operation organizations, the purpose of this paper is to propose an integrated model applicable to estimate degree of service contribution in passenger carriage in the combined public transport network. With a hypothesis that the complete electronic card system is deployed, this paper supposes every passenger's loading and alighting stations is recordable. Thereby, this paper limits research scope as to Seoul metropolitan railroad area since used route(s) between origin and destination stations can not be traceded because transfer stations each passenger path through is not recorded. Each model proposed in the paper is as follows: 1. a generalized cost reflecting passenger's transfer behavior; 2.a K path model for determining similar routes between O-D; 3.an assignment model for loading O-D trips onto the detected similar routes using Logit Model.