• Title, Summary, Keyword: 비개착공법

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Development of Trenchless Tunneling Method Using Pressurizing Support and Its Field Application (가압식 지보를 이용한 비개착 터널공법 개발 및 현장적용 사례)

  • Kim, Dae-Young;Lee, Hong-Sung;Sim, Bo-Kyoung
    • Journal of the Korean Geotechnical Society
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    • v.28 no.7
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    • pp.17-30
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    • 2012
  • A new trenchless tunneling method using pressurizing support has been developed. As it overcomes shortcomings of conventional methods, it is applied to the field. The main concept of the new method is the pressurization system which, by means of pressurization bag between outer flange of steel ribs and excavated perimeter, applies the pressure corresponding to the magnitude of the relaxed earth pressure caused by excavation to the ground to prevent ground displacement. The stability of the support members and effect of displacement control of the new method were verified through several ways such as numerical tests and various model tests. The new method was applied to the construction of a 10.7 m wide, 7.9 m high and 85 m long road tunnel that passes under Yeongdong Expressway. By applying the new method, the tunnel construction was successfully completed in 13.5 months. It decreases the construction period to 35% compared to that of conventional methods, and ground displacement was almost negligible.

A Study on the Finite Element Analysis and Management Criteria by Applying UPRS Method in the Subway Station (기존 지하철정거장 비개착공법 적용시 유한요소 해석과 관리기준에 관한 연구)

  • Cho, Byeong Joon
    • 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.

A Study on Surface Settlement Prediction Method of Trenchless Technology Pipe Jacking Method (비개착 강관압입공법의 지표침하 예측방법 연구)

  • Chung, Jeeseung;Lee, Gyuyoung
    • Journal of the Korean Geoenvironmental Society
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    • v.16 no.11
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    • pp.29-37
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    • 2015
  • Non-excavation method is needed to secure the stability of existing structures during construction. Therefore, prediction of ground settlement is essential. Causes of settlement when using steel pipe indentation method are leading pipe-steel pipe gap, excessive excavation and soil-steel pipe friction etc. Also they are similar to the causes of settlement when using Shield TBM during construction. In this study, ground settlement during steel pipe indentation is predicted by the Gap Parameter Method and Volume Loss Method which are kinds of Shield TBM prediction Method. and compared with those of prediction methods by conducting field test. As a result, Volume Loss Prediction Method is the most similar to the field tests. However, It is needed to additional studies, such as decision of the factors and adaptability for total settlement predictions of non-excavation method.

A preliminary study on the use of analytic hierarchy process for selecting a optimum trenchless excavation method (최적의 비개착공법 선정을 위한 계층분석법의 적용에 관한 기초연구)

  • Kang, Tae-Ho;Chang, Soo-Ho;Choi, Soon-Wook;Lee, Chulho;Cho, Jinwoo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.6
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    • pp.685-693
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    • 2015
  • There have been high demands for urban underground structures. However, they should be rapidly constructed while maintaining the functions of adjacent structures and road systems especially in urban areas. In this respect, trenchless excavation methods are considered to very effective in minimizing ground displacements during excavation works. A variety of field conditions such as economic, technical and environmental aspects should be taken into consideration when an optimum trechless excavation method is to be chosen in a given condition. Therefore, this study aims to carry out a fundamental study to select an optimum trenchless excavation method by the decision making technique. Especially, AHP (Analytic Hierarchy Process) which is a kind of a multiple attribute decision making process is adopted to consider the opinions of experts and to derive reliable decision criteria. As a result, the weights of key factors and the most effective trenchless methods for different ground conditions were proposed in this study.

A numerical study on the three-dimensional ground movement by the trenchless construction method of concrete box by a square steel pipe supporting system (사각형 강관을 이용한 비개착 시공에 따른 지반거동의 분석: 수치해석)

  • Choi, Soon-Wook;Park, Young-Taek;Chang, Soo-Ho;Bae, Gyu-Jin;Lee, Ki Taek;Baek, Yong Ki
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.14 no.5
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    • pp.469-484
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    • 2012
  • This study aims to numerically investigate ground movement around a square steel pipe as well as a group of square steel pipes induced by its and their ground penetration for trenchless construction of a concrete box. From numerical results, ground movement induced by a square steel pipe is much more dominantly governed by vertical displacement rather than horizontal displacement. Ground settlement induced by pipe penetration is much larger as the overburden becomes lower. The settlement is also shown to be slightly dependent upon the sequence of pipe penetration. More careful construction management is highly in demand during the penetration of upper pipes since their induced settlement occupies approximately 75 percent of total ground settlement after the whole construction of steel pipes.

Stress Release Zone Around Sub-structure Constructed by Non-open Cut Methods (비개착공법으로 건설된 지하구조물 주변 지반 응력이완영역 규명)

  • Seo, Ho-Sung;Cho, Kook-Hwan
    • Journal of the Korean Society for Railway
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    • v.19 no.4
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    • pp.480-488
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    • 2016
  • For the development of areas around railway lines, subsurface construction using the non-open cut method under the railway has recently been increased. However, when a structure under a railway is constructed, the stress release of the ground is not considered an important factor in the design. In this study, laboratory tests were conducted to determine a zone of stress relaxation. Field tests using an inclinometer were performed to measure the horizontal displacement of the ground during non-open cut construction. The stress release zone and the subgrade stiffness were investigated by numerical analysis. The results of the laboratory tests indicated that the failure zone in the ground was similar to a Rankine's active earth pressure zone. The measured data from the inclinometer in the field tests showed that displacements started when a steel pipe was pushed into the ground. The results of numerical analysis show that lateral earth pressure was also close to Rankine's active earth pressure. The roadbed support stiffness of the soil around the structure decreased to 40% of the original value. The ground around the subsurface structure constructed using nonopen cut methods should be reinforced to maintain the running stability of train.

An Experimental Study on Flexural Behavior in Framed Structure of P.S.T Method (P.S.T 공법 라멘 구조물의 휨 거동 특성에 관한 실험적 연구)

  • Cui, Jie;Yoon, Jong Nam;Eum, Ki Young;Hong, Sung Nam;Park, Sun Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.2
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    • pp.144-152
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    • 2011
  • The existing underground trenchless methods use reinforcing rod in steel tube to obtain structural stiffness. However, there are some problems such as inconvenience of work and expensive material fee which are resulted from limited working space and reinforcing work. To resolve these problems, a new trenchless method, namely P.S.T method (Prestressed Segment Tunnel Method), is developed which uses joint to connect the steel segment and form erection structure in underground construction. Further, installing strands for prestressing. In order to evaluate the flexural capacity of the P.S.T method structure, experiment was conducted. The parameters considered in the experiment are the span-to-depth ratio, diameter of steel tube at corner, prestressing force and welding of joint. Altogether examining the flexural behavior, the effect of deflection in structure according to different parameters has also been analysised.