• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.175-183
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• 2014

This study investigates the response of structures to tunnelling-induced ground movements in clay ground, varying tunnel excavation condition (tunnel depth and diameter), tunnel construction condition (ground loss), and tunnel ground condition (soft clay and stiff clay). Four-story block-bearing structures have been used because the structures can easily be characterized of the extent of damages with crack size and distribution. Numerical parametric studies have been used to investigate of the response of structures to varying tunnelling conditions. Numerical analysis has been conducted using Discrete Element Method (DEM) to have real cracks when the shear and tensile stress exceed the maximum shear and tensile strength. The results of structure responses from various parametric studies have been integrated to consider tunnel excavation condition, tunnel construction condition, and tunnel ground condition and provide a relationship chart among them. Using the chart, the response of structures to tunnelling can easily be evaluated in practice in clay ground.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.175-187
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• 2015

In this paper, the development of trench shield machine for near-surface railway construction were presented. The Near-surface railway can be constructed by cut and cover construction method, because it is installed at the depth of 5~7 m below roads. The cut and cover construction method mostly use temporary supports. The limitation of the cut and cover method is high installation cost and long construction period. To overcome these disadvantages, development of the trench shield machine is proposed and expected to shorten the construction time and cost of near-surface railway system. The sliding retaining wall of trench shield equipment replaces the role of temporary support (solider piles and lagging) and excavator equiped to the bottom front of the machine shorten the excavation time. This paper deals with design of the bit attached to the excavator and required capacity of the motor.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.171-186
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• 2010

It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than in the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system or change of ground condition happen during construction process, lots of axial force can be induced in some struts, which threaten the safety of construction. This paper introduces two examples of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. The characteristics of ground deformation and strut axial force change, which were measured in the sections of two examples that are 50 meters apart in one construction site and have almost similar design and construction conditions were analysed, the similarity and difference between measurement results of two examples were compared and investigated. This article aims to improve and develop the technique of design and construction in future projects having similar ground condition and supporting method.

• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.3
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• pp.26-36
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• 2019

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03a
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• pp.410-430
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• 2004

근년에 와서 터널이 건설 프로젝트의 주요 분야로서 국가 건설인프라의 중심 축으로 떠오르는 분야임을 감안할 때 그 중요성은 건설분야뿐만 아니라 국가기본사업 및 사회 간접시설 등 전반에 걸쳐 있다. 국내 터널 기술은 재래식 굴착에서 근접시공, 도심지 연약지반 통과, 대단면 굴착 등으로 이어져 그 한계에 도전하고 있다. 또한, 세계적 추세인 기계화 시공에 대해서도 진일보하고 있다. 최근의 전파, 기계, 정보통신 기술의 발달은 터널 현장에서 기계화 시공의 비율이 높아지도록 견인하고 있으며 삶의 질 향상과 더불어 일반적인 터널의 기능에 첨가하여 쾌적한 터널을 요구하는 실정이다.(중략)

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.217-221
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• 2005

도시의 기능이 날로 커져가고 땅속 지하매설물은 포화상태에 이르렀다. 또한 시민들의 의식 수준이 높아가면서 도시에서의 굴착시공은 민원유발과 교통소통장애 문제로 날로 어려워지고 있는 것이 현실이다. KT에서는 무인 및 유인 통신구를 건설할 수 있는 장비를 이미 개발한바 있으며, 본 연구를 통해 도심지에서 보다 효율적으로 통신관로 ${\Phi}50mm,\;{\Phi}150mm,\;{\Phi}300mm$를 시공할 수 있는 장비를 개발하게 되었다. 도시는 복잡하기 때문에 비개착 시공에 있어서 시공 점용면적이 상대적으로 많을 경우 어려움을 겪게된다. 소구경 비개착 장비인 XS-300은 길이 1.45m 폭 0.8m 높이 0.97m 이며 중량은 700kg인 소형장비인 것이 특징이다. XS-300은 도심지에서 통신맨홀 터파기 부분을 압입구로 활용할 수 있으며 경제적인 비용으로 개착식 시공이 불가한 구간에 대한 인입관로 구성과 지하장애물 하월시공, 도로횡단 시공 시에 적합한 장비이다. 특히 타 시설물을 관통한 불량통신시설과 재해에 취약한 통신시설에 대해 안전하고 경제적인 비용으로 이설시공을 할 수 있으며 통신인프라 기초시설 안정화 및 품질고도화에 기여할 수 있을 것이다.

• Explosives and Blasting
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• v.37 no.2
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• pp.22-30
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• 2019

On sites where explosives are used, the effects of noise and vibration produced by the blast wave are subject to a number of operational restrictions. Recently, the number of civil complaints has increased and the standard of environmental regulations on secure goods has been greatly tighten. Therefore, work is generally carried out by machine excavation in case of close proximity of safety thing. Machine excavation methods have the advantage as reducing noise and vibration compared to blasting methods, but depending on the conditions of rock intended to be excavated, they are sometimes less constructive than planned. In general, the closer a rock type is to hard rock, the less constructible it becomes. In this paper, we are going to explain the construction of a construction section with a close proximity to a safety thing using electronic detonators. While the project site was designed with a machine excavation methods due to the close(9.9m) proximity of safety thing(the railroad), construction using electronic detonators was reviewed as an alternative method for improving rate of advance time and construction efficiency when expose to hard rock. Through blasting using electronic detonators, construction and economic efficiency were maximized while minimizing impact on surrounding safety things. Because $HiTRONIC^{TM}$, which is produced by Hanwha, has innovative stability and high explosion reliability, it is able to explode with high-precision accuracy. Electronic detonators are widely used in construction sites of railway or highway, other urban burrowing areas and large limestone mines.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.167-174
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• 2002

In this study, a numerical stability analysis was performed for a large tunnel considering excavation sequence. In most cases, stability of a tunnel is analyzed based on the stability of the final excavation stage only. In this study, stability analysis of a tunnel was performed at each excavation stage. In summary, it can be inferred that there is no problem in stability of the tunnel. However, thorough and careful measurements are recommended. Also, it is found that the stability of the tunnel at the 5th excavation stage when the right half of the main tunnel is excavated is rather lower than that of the tunnel at the final excavation stage.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.6
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• pp.605-614
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• 2015

A room-and-pillar underground structure is characterized by its grid-type array of room and pillar. As a result, its construction and economical efficiency can be governed by excavation sequence. In this study, the construction period by the drill and blast method which can be treated as a main sequence for excavation was examined by considering the regulation for blasting and construction standard of estimation in Korea. To evaluate the construction period for the room-and-pillar underground structure constructed in 4 kinds of square-type area ($30{\times}30{\sim}57{\times}57m$), the concurrent excavation pattern which was suggested in the previous researches was used. From the suggested condition, the total construction period by drill-and-blast method can be estimated with the consideration of the construction area, number of jumbo drill and faces in operation.

• Explosives and Blasting
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• v.32 no.2
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• pp.16-24
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• 2014

In this "Wonju~Jaecheon double-lanes railroad" project, a highway is located at about 13meter above a tunnel. Initially, rock-splitting method was used for the tunnel excavation in order to minimize the possible damage on the highway. The method, however, takes a long time for the tunnel excavation and that may cause other problems like large displacement of tunnel and subsidence of highway ground before the tunnel can be stabilized by supporters. Therefore, the application of electronic blasting method(eDdevII) was recommended to control the blast vibration below 1.0cm/sec as well as to prevent the subsidence of highway ground. The analysis of the influence of tunnel excavation on the highway showed that electric blasting method is permissible for the safe management of the highway. Based on that, the tunnel construction under a highway could be carried out quickly and safely without any damages on the highway.