• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.63-72
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• 2017

This study estimates the degree of influence of factors influencing ground surface settlement during tunnel excavation using Shield tunneling trough 3D FE-analyses. Numerical analysis was carried out by considering face pressure, skinplate pressure, excavation length, soil model, element size and soil material properties. Also, Actually constructed shield TBM comparative analysis was conducted by compared with Volume loss model, Pressure model and field measurement data. Skinplate pressure and soil model were the most influential factors, and the analysis results were similar to field measurements when the appropriate skinplate pressure was applied according to the passing stratum.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.177-184
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• 1999

In soft ground tunneling, shield method is very good for safety of neighboring structures. Although shield tunnel method has the merits to minimize the deformation of ground around tunnel, ground deformations occurred until the material grouted in tail void hardens are inevitable. In this study, the effects of micropile used as one method to restrain the settlement of neighboring structures by the tail void are studied by laboratory model tests. As a basic test result, the effective direction of micropile and the restraint rate of settlement by micropile reinforcement are known.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.757-762
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• 2007

The lining segment which is the main structure of the shield tunnel consists of joints, not continua. Past international and domestic design data have been commonly used for design practices without specific verification about the structural analysis model, design load, and affection of the soil constant of the lining segment. In this study, the propriety is estimated through the comparison between analytical solution and numerical solution for segment analysis and design models of the shield tunnel which is being used internationally and domestically. As a result, the full. circumferential beam jointed spring model (1R-S0) is suggested by considering aspects of convenient use, application to field condition, and accuracy of analysis result. With suggested model, the parameter analysis was conducted for joint stiffness, ground rigidity, joint distribution, and joint number.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.265-281
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• 2017

For shallow tunnel constructions, settlement of the ground surface is a main issue. Recent technical developments in shield TBM tunneling technique have enabled a decrease in such settlements based on tunneling with ground deformation controls. For this objective, the tail void grouting is a common practice. Generally surface settlements in a soil of low permeability occur during a tunnel construction but also during a long period after completion of the tunnel. The long-term settlements occur mainly due to consolidation around the tunnel. The consolidation process is caused and determined by the tail void grouting which leads to an excess pore water pressure in the vicinity of the tunnel. Because of this, the grouting pressure has a strong effect on the long-term settlements in the shield tunneling. In order to investigate this effect, a series of coupled hydro-mechanical 3D finite element simulations have been performed. The results show that an increase in grouting pressure reduces the short-term settlements, but in many cases, it doesn't lead to a reduction of the final settlements after the completion of consolidation. Thereby, the existence of a critical grouting pressure is identified, at which the minimal settlements are expected.

• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.483-496
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• 2013

This paper presents the shield TBM technology in soft ground tunnelling. In order to perform this study, a scale model test was carried out using the developed small scaled shield TBM machine. The various instrumentations were conducted during the simulation of tunnelling. In addition, the ground behavior due to the shield TBM operation parameters was measured during the simulation. Based on the simulation results, the stability of the ground was evaluated and the fundamental shield TBM tunnelling technique in the soft ground was suggested. In conclusion, design's reliability through laboratory small scale model test about Shield-TBM section was obtained, and both the improvement plan for safety during construction and the construction plan for securing airport runway's safety during tunnel passing by Shield-TBM propulsion were suggested.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.305-317
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• 2015

This paper is to perform 3-dimensional numerical analysis considering face pressure, backfill pressure, excavation length, soil model and element size for selecting key factors of ground surface settlement due to shield TBM advancement. According to the numerical analysis results, backfill pressure and soil model are governing factors inducing ground surface settlement. To complement this study, the ground conditions and characteristics of the boring machine will be considered using numerical analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.25-32
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• 2001

Doosan Construction & Engineering Co., Ltd is building a railway tunnel beneath the Soo-Young River connecting MinLak Station and Centum City Station, a section 230, subway line 2, Pusan City, Korea. When completed the tunnel will have a finished inner diameter of 6.5m(21.311) throughout its total length of 840m(420m = 0.52 miles, Two Single Track Tunnel : 420m＋420m). The ground profile of the face toward shield machine is composed of multi layers, silty clay, clayey gravel, soft rock etc. This research paper is to predict ground deformation and variation of stresses around tunnel using Hyperbolic model, and to reflect the works on the next shield tunneling project. And this research paper is analyzed data of measuring instrument (such as settlement gauge, inclinometer, Multiple extensometer, etc.) which is installed along tunnel line for safety of tunnel. For calculations, the finite difference Method is applied. Backfill grouting material is supposed to have instantly strength of 10kg/$\textrm{cm}^2$ above, although its strength is available after 24 hours passed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.985-997
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• 2017

In many countries, most of the tunneling works have been ordered by the shield TBM, and also Korean companies are actively bidding and execute in this project. In case of Korea, refurbished machines are mainly using in power cable, gas pipelines, and water and sewage tunnel. Also in metro projects, shield TBM of over diameter 7m is required mainly by using brand new machine. Since the shield TBM is not easy to change once it is produced, it is necessary for the client to provide sufficient information on the production conditions so as to satisfy various characteristics of the construction. In this study, to manufacturing optimal shield TBM, the Client's TBM requirements of tunnel construction in Hong Kong and UK was analyzed and compared with the domestic requirements. The results are expected to provide as client's guidelines for bidding stage and manufacturing for shield TBM tunneling in Korea in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.513-525
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• 2018

A 3 dimensional numerical analysis for shield TBM tunnel should take into account various characteristics of the shield TBM excavation, such as gap, tail void, segment installation, and backfill injection. However, analysis method considering excavation characteristics are generally mixed with various method, resulting in concern of consistency and reliability degradation of the analytical results. In this paper, a parametric study is carried out by using actually measured ground settlement data on various methods that can be used for 3 dimensional numerical analysis of shield TBM tunneling. As a result, we have analyzed and arranged an analytical method to predict similarly the behavior of ground settlement and tunnel face pressure at the design stage. Skin plate pressure, backfill pressure and soil model have been identified as the most significant influences on the ground settlement. The grout pressure model is considered to be applicable when there is no volume loss information on the excavated ground, such as seabed tunnels, or when it is important to identify the behavior around a tunnel, such as surface settlement as well as face pressure. And it is considered that designers can use these guidelines as a base material to perform a reasonable 3 dimensional numerical analysis that reflects the ground conditions and the features of the shield TBM tunneling.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.3
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• pp.305-318
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• 2016

This study is to evaluate the uncertainty of the soil parameters associated with the Gap parameter during shield TBM tunnel excavation of ${\bigcirc}{\bigcirc}$ International Airport Terminal 2 connecting railway construction basic design. And This study is to evaluate the adequacy of the shield TBM design by performing a reliability analysis of the Surface settlement. In addition, By analyzing the reliability indices of the design constants and Sensitivity probability of failure to be used in designing an integer parameter Gap, and By evaluating the design constants of a great influence on the surface subsidence, it was to provide a basis for carrying out an optimum design.