• Title, Summary, Keyword: Reinforcement lining

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Model Test of Lining for Estimation of Tunnel Soundness (터널 건전도 평가를 위한 라이닝 모델실험)

  • Kim, Young Keun
    • Magazine of korean Tunnelling and Underground Space Association
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    • v.1 no.2
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    • pp.59-71
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    • 1999
  • Recently, many deformations in tunnel such as crack and leakage were occulted. Specially, the defects of tunnel lining have been a serious problem in safety and stability many repair works for maintenance in tunnel have been carried out. Therefore, it is necessary to estimate the structural cracking for countermeasure in deformed tunnel and to investigate on the characteristics of lining system and the soundness of tunnel. In this study model tests for tunnel lining were carried out using test apparatus and centrifuge, In the direct loading test, the prototype was Kyungbu high-speed railway tunnel and the scale is 1/10, and lining models were made of concrete. Test conditions included load conditions such as direction, shape and type, lining conditions such as single and double lining, thickness, and reinforcement. In centrifuge model test, the prototype was Seoul subway tunnel and the scale is 1/100, and lining models were made of aluminum and hydrostone. Test conditions included tunnel defects such as thickness shortage. behind cavity and longitudinal cracks, reinforcement methods such as epoxy, grouting and carbon sheet. From these model tests , the characteristics of deformation and failure for tunnel lining were estimated, and the structural behaviors of deformed lining and the effects of repair and reinforcement for tunnel lining were researched.

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Case Studies of Automatic Measurement and strength for Damage in the Public Tunnel (공용중인 터널의 변상에 대한 보강 및 자동화계측 사례)

  • Han Ja-Jung;Kim Young-Ho;Jang Gi-Soo;Kweon Young-Jung;Ahn Sang-Ro
    • 한국터널공학회:학술대회논문집
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    • pp.270-281
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    • 2005
  • An especial attention for old tunnel safety is required on increasing of The various tunnel recently. Specially, the lining investigation method of the old tunnel will be able to presume condition of concrete lining indirectly. Because it is many restriction thought of environment and ground condition investigation method of tunnel lining rear. This study carried out section & convergence measurement of part which was deformed in tunnel lining. It had been observed for the change of tunnel behavior with a continuous measurement. It has been analyzed for a cause of tunnel deformation and inspected for the effect after a repair-reinforcement to tunnel compared with the effect before those by structure analysis. By establishing automatic measurement system after repair-reinforcement to tunnel, it would be accomplished to convergence measurement continually. As a result, it was observed that deflection and deformation of tunnel was convergent. but it should be followed to a continuous maintenance because of unstable ground condition, cause of inner tunnel, environment. The railroad tunnel which was executed a reinforcement of the tunnel lining must investigate the close condition of reinforcement lining and concrete lining.

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New reinforcement algorithms in discontinuous deformation analysis for rock failure

  • Chen, Yunjuan;Zhu, Weishen;Li, Shucai;Zhang, Xin
    • Geomechanics and Engineering
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    • v.11 no.6
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    • pp.787-803
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    • 2016
  • DDARF (Discontinuous Deformation Analysis for Rock Failure) is a numerical algorithm for simulating jointed rock masses' discontinuous deformation. While its reinforcement simulation is only limited to end-anchorage bolt, which is assumed to be a linear spring simply. Here, several new reinforcement modes in DDARF are proposed, including lining reinforcement, full-length anchorage bolt and equivalent reinforcement. In the numerical simulation, lining part is assigned higher mechanical strength than surrounding rock masses, it may include multiple virtual joints or not, depending on projects. There must be no embedding or stretching between lining blocks and surrounding blocks. To realize simulation of the full-length anchorage bolt, at every discontinuity passed through the bolt, a set of normal and tangential spring needs to be added along the bolt's axial and tangential direction. Thus, bolt's axial force, shearing force and full-length anchorage effect are all realized synchronously. And, failure criterions of anchorage effect are established for different failure modes. In the meantime, from the perspective of improving surrounding rock masses' overall strength, a new equivalent and tentative simulation method is proposed, it can save calculation storage and improve efficiency. Along the text, simulation algorithms and applications of these new reinforcement modes in DDARF are given.

A Case Study on Deformation Conditions and Reinforcement Method of Cavity behind the Lining of Domestic Old Tunnel (국내 재래식 터널의 변상현황과 배면공동 보강 사례연구)

  • Kim, Young-Muk;Lim, Kwang-Su;Ma, Sang-Joon
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1343-1350
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    • 2005
  • In this study, the whole deformation conditions of domestic old tunnels and reinforcement methods for deformation tunnels were investigated and analysed, and the present conditions, occurrence cause and reinforcement methods of cavity behind the tunnel lining were investigated and analysed comprehensively. The deformation causes of domestic old tunnels could be classified in three kinds : change of earth pressure operating tunnel ground, material problem of concrete lining, mistake of design and construction. As a result of analysis, the tunnel deformation was occurred by not specific cause but various cause As a result of investigation for 455 domestic tunnel data, more than 70% of the tunnel deformation was related to leakage and the other deformation cause also accompanied leakage mostly. An applied reinforcement method was related to leakage and flood prevention measures, but application of reinforcement method for boundary area between tunnel and ground and tunnel periphery which influence on the tunnel stability was still defective. The cavity of domestic old tunnel occupied about 16% of the total tunnel length and about 68% of cavity was located in the crown of tunnel, and besides, the occurrence cause of cavity was analysed to design, construction and management cause. The filling method for cavity using filling material was comprehensively appling to cavity behind tunnel lining.

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A two-phase interface element for simulation of lining systems

  • Liu, X.;Scarpas, A.;Blaauwendraad, J.
    • Structural Engineering and Mechanics
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    • v.11 no.5
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    • pp.547-564
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    • 2001
  • The numerical formulation of a two-phase interface element appropriate for porous lining system is presented. The formulation is isoparametric and can be applied both for 2-D and 3-D analysis. Biot's theory is utilized as the basis for the development of the element constitutive theory. In order to be capable of simulating the reinforcing characteristics of some geotextiles utilized as lining system, a reinforcement component has also been implemented into the formulation. By employing this specially developed interface finite element, the influence of soil consolidation on the stress distribution along the lining system of a reservoir and a landfill has been investigated.

Application of SFRC as a lining material in tunnels (터널라이닝 구조재로서 SFRC 적용에 관한 연구)

  • Yi, Sang-Keun;Kim, Dong-In;Jo, Gyu-Seung
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.3 no.4
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    • pp.25-34
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    • 2001
  • As the topography of Korea consists of mountains at about seventy percent, there is necessarily an increasing demand for tunnel construction according to the expansion of the existing highway and construction of new highway. The concrete lining of tunnel portals has been designed with reinforced concrete to resist the cracking due to the difference in temperature in the inside and outside of tunnel. In the paper, the application of steel fiber reinforcement concrete was analyzed as the lining concrete at tunnel portals and through structure analysis and field model test the suitability of the steel fiber reinforcement concrete was assessed as the lining member of tunnel portal.

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An Analysis Model of the Secondary Tunnel Lining Considering Ground-Primary Support-Secondary Lining Interaction (지반-1차지보재-2차라이닝의 상호작용을 고려한 터널 2차라이닝 해석모델)

  • 서성호;장석부;이상덕
    • Tunnel and Underground Space
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    • v.12 no.2
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    • pp.107-114
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    • 2002
  • It is the common practice to over design the reinforcement for the secondary tunnel lining due to the lack of rational insight into the ground loosening loads. and due to the conservative application of the empirical design methods. The main loads of the secondary lining are the ground Loosening loads and the ground water pressure, and the ground load is critical in the reinforcement design of the secondary lining in the case of drained tunnel. If the external load is absent around a tunnel, the reasons of the load far secondary tunnel lining are the deterioration of the primary supports such as shotcrete, steel rib, and rockbolts. Accordingly, the analysis method considering the ground-primary supports-secondary lining interaction should be required tar the rational design of the secondary tunnel lining. In this paper, the interaction was conceptually described by the simple mass-spring model and the load transfer from the ground and primary supports to the secondary lining is showed by the ground-primary supports-secondary lining reaction curves fur the theoretical solution of a circular tunnel. And also, the application of this proposed model to numerical analysis is verified in order to check the potential far the tunnel with the complex analysis conditions.

Variation of Earth Pressure Acting on the Cut-and-Cover Tunnel Lining due to Geotextile Mat Reinforcement (지오텍스타일 매트의 설치에 의한 개착식 터널 라이닝에 작용하는 토압의 변화)

  • Bautista, F.E.;Park, Lee-Keun;Im, Jong-Chul;Joo, In-Gon
    • Journal of the Korean Geotechnical Society
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    • v.23 no.3
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    • pp.25-40
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    • 2007
  • Excessive earth pressure is one of the major mechanical factors in the deformation and damage of Cut-and-Cover Tunnel lining in shallow tunnels and portals of mountain tunnels (Kim, 2000). Excessive earth pressure may be attributed to insufficient compaction and consolidation of backfill material due to self-weight, precipitation and vibration caused by traffic (Komiya et al., 2000; Taylor et al., 1984; Yoo, 1997). Even though there were a lot of tests performed to determine the earth pressure acting on the tunnel lining, unfortunately there were almost no case histories of studies performed to determine remedial measures that reduce differential settlement and excessive earth pressure. In this study the installation of geotextile mat was selected to reduce the differential settlement and excessive earth pressure acting on the cut-and-cover tunnel lining. In order to determine settlement and earth pressure reduction effect (reinforcement effect) of geotextile mat reinforcement, laboratory tunnel model tests were performed. This study was limited to the modeling of rigid circular cut-and-cover tunnel constructed at a depth of $1.0D\sim1.5D$ in loose sandy ground and subjected to a vibration frequency of 100 Hz. Model tests with varying soil cover, mat reinforcement scheme and slope roughness were performed to determine the most effective mat reinforcement scheme. Slope roughness was adjusted by attaching sandpaper #100, #400 and acetate on the cut slope surface. Mat reinforcement effect of each mat reinforcement scheme were presented by the comparison of earth pressure obtained from the unreinforced and mat reinforced model tests. Soil settlement reduction was analyzed and presented using the Picture Analysis Method (Park, 2003).

Optimized Cross-section Suggestion of a New Concept Lining Board through Parametric Study (매개변수해석을 통한 신개념 복공판의 최적단면 제안)

  • Kim, Chun-Ho;Yi, Seong-Tae;Kim, In-Sic;Sim, Tae-Mu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.2
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    • pp.84-91
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    • 2015
  • In this paper, to overcome disadvantages of existing lining boards, the parametric studies to evaluate safety and verify performance of newly suggested lining boards was performed. Since the calculated stresses of steel plates are lower than the allowable stress for considered all analytical variables, end reinforcement locations, and crane rail loads, it can be concluded that the suggested lining board is structurally safe. Where, "$3,000{\times}2,000{\times}6t$" was select to be optimized cross-section and the reinforcement from the end to 200mm to the internal direction looks like the best case. In addition, the suggested lining board is economical since the steel amount per unit area compared to existing lining board is reduced by 36% and it can apply to the lining structural system of subway and underpass since construction speed is past due to the less installation number of lining boards.

TBM segment lining section design of hypothetical subsea tunnels (가상 해저터널 TBM공법 적용 시 세그먼트 단면설계)

  • Choi, Jung-Hyuk;Yoo, Chung-Sik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.1
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    • pp.49-63
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    • 2015
  • In this paper, the results of evaluation on the member forces in the virtual subsea tunnel lining segments and optimal thickness of the segment with changes in depth were presented. To evaluate member forces on the hypothetical subsea tunnelling cases were developed and the segmental lining member forces were calculated by performing structural analysis using the 2-Ring Beam model. Through a preliminary reinforcement design review of the cross-section using calculated member force, optimal reinforcement design was selected. Based on the results, the variations of member forces with construction conditions such as the cover depth and the hydraulic pressure are presented. In addition, optimum segment lining designs were developed for various tunnelling conditions.