• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.6
• /
• pp.725-744
• /
• 2022

As the construction of infrastructure using the underground tunnel in urban area have been rapidly increased, various accidents and collapses of tunnel including structure have been occurred in deep urban tunnelling. The concern and worry relating to the risk and safety of the tunnel during excavation is becoming the key issues in deep urban tunnelling. In this study, it was conducted for deep urban tunnel at GTX (Great Train Express) line which was located in Seoul metropolitan area to determine the risk characteristics for tunnel according to urban tunnelling. Also, it was reviewed the risk analysis and evaluation of the tunnel, shaft and station. And after a review of risk analysis and evaluation for risk register and hazard identification by using a risk matrix method, safety management of the tunnel according to excavation was evaluated to be secured. This study is expected to be applied as useful approach in deep urban tunnelling if you need to review the risk and safety management system of tunnel according to mitigation measures in complex urban tunnelling.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.9 no.3
• /
• pp.229-240
• /
• 2007

The 3D absolute displacement monitoring system has been developed to analyze the tunnel convergence measured under construction of underground structures and to manage effectively the measured data. The system is comprised of the total station, the anchor-typed target pin and the 3D absolute displacement measurement and management program. In this paper, the types and specifications of the 3D total station were presented. The anchor-typed target pin, an improved model of traditional one, was developed and its sightable distance and measurement accuracy were checked by field tests. Also a 3D absolute displacement measurement and management program, TEMS 3D, was developed to provide some analysis tools including the trend and influence lines. L/C ratio, S/C ratio and the like. The developed system was applied the construction stage of a railway tunnel for testing purpose. It is verified that the developed system is capable of predicting weak zones ahead of tunnel face by comparing with results of TSP (Tunnel Seismic Prediction) survey.

• The Journal of Engineering Geology
• /
• v.25 no.3
• /
• pp.395-401
• /
• 2015

An investigation of the tunnel face, as well as related measurement data collected during tunneling, is necessary for rock classification and to determine tunnel stability and the cost efficiency of tunneling. However, systematic management and efficient use of such data have yet to be successfully implemented domestically, and the number of experts in this field in Korea is limited. Thus, measures to develop and implement systematic management and effective use of data and expertise are urgently needed. This study aimed to develop measures to efficiently provide online tunnel design and construction data using a building information model (BIM)-based data visualization approach, based on an integrated 3D tunnel model generation module and a web viewer module. The development technology was verified through ○○ tunnel design and construction. Directions for future study and system improvement are proposed.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.23 no.6
• /
• pp.403-421
• /
• 2021

Most of the urban tunnels in Korea, which are represented by the 1st to 3rd subways, use the drainage tunnel by NATM. Recently, when a construction project that actively utilizes large-scale urban space is promoted, negative effects that do not conform to the existing empirical rules of urban tunnels may occur. In particular, there is a high possibility that groundwater fluctuations and hydrodynamic behavior will occur owing to the practice of tunnel technology in Korea, which has mainly applied the drainage tunnel. In order to solve the problem of the drainage tunnel, attempts are being made to control groundwater fluctuations. For this, the establishment of tunnel groundwater management standard concept and the analysis of the tunnel hydraulic behavior were performed. To prevent the problem of groundwater fluctuations caused by the construction of large-scale tunnels in urban areas, it was suggested that the conceptual transformation of the empirical technical practice, which is applied only in the underground safety impact assessment stage, to the direction of controlling the inflow in the tunnel, is required. And the relationship between the groundwater level and the inflow of the tunnel required for setting the allowable inflow when planning the tunnel was derived. The introduction of a tunnel groundwater management concept is expected to help solve problems such as groundwater fluctuations, ground settlement, depletion of groundwater resources, and decline of maintenance performance in various urban deep tunnel construction projects to be promoted in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.12
• /
• pp.677-685
• /
• 2018

In construction, schedule management is the basic but important step, for the effective schedule management, the preparation of the reasonable schedule table should be prioritized. In the design stage, the optimal construction period can be selected through comparison of various conditions and construction methods considering weather conditions and site characteristics. But, At the planning phase, it is difficult to select the effective method and calculate the proper construction period by the basic data(D/B) analysis. In this paper, the construction method considering characteristics of each type and conditions of existing city was selected. For the reasonable duration calculation, we analyzed the unit schedule for RC method for open type and Shield TBM method for tunnel type. The normal project duration of construction assuming of 1,200m of extension and every 200m of ventilation was prepared by integrating each unit schedule. It was analyzed that it took 893 days for the open type and 616 days for the tunnel type. The results of this study will help to make type selection and normal project duration more easily in the planning phase. If it is linked to the design stage, it will be easy to estimate the process and construction cost.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.234-239
• /
• 2004

Recently, the tunnel structures are increasing. And the tunnels are to be large diameter tunnel and long. Therefore, inspection, repair, and maintenance of tunnels are an extremely important part of infrastructure management, with particular technical and safety considerations arising from the very nature of underground construction. To inspect surface state of tunnels, concrete structures, it must generally use method of conventional visual inspection, but this method is very not objective. To measure the width, length, position, direction of a crack, it is very difficult, when the tunnel is long span and high rise. Thus, to make up for this demerits, in this paper is proposed the Tunnel Scanning System that we can check conditions of the tunnel structures quickly, detect the detailed data objectively, count automatically the width of a crack by the original software and follow the trend of long tenn changes in the condition of a tunnel.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.22 no.2
• /
• pp.155-170
• /
• 2020

In this paper, a risk management system applicable to NATM tunneling projects is proposed. After investigating case histories in NATM tunnel collapse, this paper analyzes the potential risk factors and their corresponding risk events during NATM tunnel construction. The risk factors are categorized into three groups: geological, design and construction risk factors. The risk events are also categorized into four types: excessive deformation, excessive deformation with subsidence, collapse inside tunnels, and collapse inside tunnels with subsidence. The paper identifies risk scenarios in consideration of the risk factors and proposes a risk analysis/evaluation method for the NATM tunnel risk scenarios. Based on the evaluation results, the optimal mitigation measure to handle the risk events is suggested. In order to effectively facilitate a series of risk management processes, it is necessary to develop a risk register and a management ledger for risk mitigation measures that are customized to NATM tunnels. Lastly, the risk management for an actual NATM tunnel construction site is performed to verify the validity of the proposed system.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.18 no.1
• /
• pp.1-12
• /
• 2016

When utilizing a Tunnel Boring Machine (TBM) for tunnelling work, unexpected ground conditions can be encountered that are not predicted in the design stage. These include fractured zones or mixed ground conditions that are likely to reduce the stability of TBM excavation, and result in considerable economic losses such as construction delays or increases in costs. Minimizing these potential risks during tunnel construction is therefore a crucial issue in any mechanized tunneling project. This paper proposed the potential risk events that may occur due to risky ground conditions. A resistivity survey is utilized to predict the risky ground conditions ahead of the tunnel face during construction. The potential risk events are then evaluated based on their occurrence probability and impact. A TBM risk management system that can suggest proper solution methods (measures) for potential risk events is also developed. Multi-Criterion Decision Making (MCDM) is utilized to determine the optimal solution method (optimal measure) to handle risk events. Lastly, an actual construction site, at which there was a risk event during Earth Pressure-Balance (EPB) Shield TBM construction, is analyzed to verify the efficacy of the proposed system.

• Journal of the Society of Disaster Information
• /
• v.16 no.1
• /
• pp.10-20
• /
• 2020

Purpose: Analyze the results of on-site inspection of the tunnel structure maintenance management monitoring and suggest improvement plans. Method: We investigate and analyze the problems of various items on maintenance monitoring of tunnel structure of 14 subway lines of Seoul subway in downtown area. Result: The maintenance monitoring items, measurement quantity and installation location are classified into open tunnel and excavation tunnel and improvement plans are suggested respectively. Various durability criteria of the measuring instruments were examined, and durability confirmation method suggested improvement measures such as approval, inspection, inspection and testing, calibration of monitoring sensors. Conclusion: Applying the improvement measures of the tunnel structure maintenance monitoring to the construction site will increase the efficiency of the maintenance monitoring and contribute to the development of construction monitoring technology.

• Earthquakes and Structures
• /
• v.23 no.3
• /
• pp.259-269
• /
• 2022

In this study, we introduce a canonical correlation analysis method to accurately assess the tunnel damage potential of ground motion. The proposed method can retain information relating to the initial variables. A total of 100 ground motion records are used as seismic inputs to analyze the dynamic response of three different profiles of tunnels under deep and shallow burial conditions. Nine commonly used ground motion parameters were selected to form the canonical variables of ground motion parameters (GMP_CCA). Five structural dynamic response parameters were selected to form canonical variables of structural dynamic response parameters (DRP_CCA). Canonical correlation analysis is used to maximize the correlation coefficients between GMP_CCA and DRP_CCA to obtain multivariate ground motion parameters that can be used to comprehensively assess the tunnel damage potential. The results indicate that the multivariate ground motion parameters used in this study exhibit good stability, making them suitable for evaluating the tunnel damage potential induced by ground motion. Among the nine selected ground motion parameters, peck ground acceleration (PGA), peck ground velocity (PGV), root-mean-square acceleration (RMSA), and spectral acceleration (Sa) have the highest contribution rates to GMP_CCA and DRP_CCA and the highest importance in assessing the tunnel damage potential. In contrast to univariate ground motion parameters, multivariate ground motion parameters exhibit a higher correlation with tunnel dynamic response parameters and enable accurate assessment of tunnel damage potential.