• Title/Summary/Keyword: Tunnel Displacement

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Current Collection Performance of Catenary System within Tunnel Section (터널구간 가선계의 집전성능)

  • Son Gun-Ho;Lee Seung-Il;Choi Yeon-Sun
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.767-772
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    • 2004
  • A dynamic simulation program of a catenary-pantograph system including tunnel section and transient section is developed in this study. The simulation program can accommodate for the pantograph of two panheads and three d.o.f model. Using the developed program, the dynamic characteristics with a SCHUNK'S WBL 85-PANTOGRAPH is analyzed at the conventional TAEBAEK line and its tunnel section when the catenary system is supported by a tunnel bracket. The simulation results show that the variation of contact force and uplift displacement is allowable in general section and the entrance and exit of a tunnel, but the uplift displacement and the separation ratio within tunnel section is difficult to allow.

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A new formulation for calculation of longitudinal displacement profile (LDP) on the basis of rock mass quality

  • Rooh, Ali;Nejati, Hamid Reza;Goshtasbi, Kamran
    • Geomechanics and Engineering
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    • v.16 no.5
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    • pp.539-545
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    • 2018
  • Longitudinal Displacement Profile (LDP) is an appropriate tool for determination of the displacement magnitude of the tunnel walls as a function of the distance to the tunnel face. Some useful formulations for calculation of LDP have been developed based on the monitoring data on site or by 3D numerical simulations. However, the presented equations are only based on the tunnel dimensions and for different quality of rock masses proposed a unique LDP. In the present study, it is tried to present a new formulation, for calculation of LDP, on the basis of Rock mass quality. For this purpose, a comprehensive numerical simulation program was developed to investigate the effect of rock mass quality on the LDP. Results of the numerical modelling were analyzed and the least square technique was used for fitting an appropriate curve on the derived data from the numerical simulations. The proposed formulation in the present study, is a logistic function and the constants of the logistic function were predicted by rock mass quality index (GSI). Results of this study revealed that, the LDP curves of the tunnel surrounded by rock masses with high quality (GSI>60) match together; because the rock mass deformation varies over an elastic range.

A Study on Behaviour of Tunnel Considering the Location of Groundwater Leaching and Fault Fracture Zone under Tunnel Construction (지하수 용출과 단층파쇄 위치에 따른 터널 거동 연구)

  • Son, Yongmin;Kim, Nagyoung;Min, Kyungjun
    • Journal of the Korean GEO-environmental Society
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    • v.16 no.12
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    • pp.37-43
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    • 2015
  • Ground characteristics is important in tunnel structure utilizing the strength of underground. In the case of the fault fracture zone such as weak soil conditions exists in the tunnel section and groundwater leaching occurs at the same time, it happens to occur to excessive displacement or collapse of tunnel frequently. Fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel under construction. Behavior of fault fracture zone is determined depending on the size and orientation of the surface portion of the tunnel. If the groundwater occurs in the face of tunnel, groundwater causes displacement and collapse. And the collapse characteristics of tunnel is a major factor in determining that the time-dependent behavior. It is difficult to accurately predict groundwater leaching from the fault fracture zone in the numerical analysis method and analyze the interaction behavior of groundwater and fault fracture zone. Therefore numerical analysis method has limitations the analysis of ground water in the ground which the fault fracture zone and groundwater occurs at the same time. It is required to comprehensively predict the behavior of tunnel and case studies of tunnel construction. Thus, the location of fault fracture zone is an important factor that determines the direction of displacement and the collapse of the tunnel. In this study, behavior characteristics of the tunnel according to the location of the fault fracture was analyzed.

Development of 3D absolute displacement monitoring system and its application at the stage of tunnel construction (터널 시공 중 3차원 절대변위 계측시스템의 개발과 적용)

  • Bang, Joon-Ho;Kim, Ki-Young;Jong, Yong-Hun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.9 no.3
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    • pp.229-240
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    • 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.

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Numerical analysis of tunnelling-induced ground movements (터널굴착으로 발생한 지반거동에 대한 수치해석적 분석)

  • Son, Moo-Rak;Yun, Jong-Cheol
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.11 no.3
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    • pp.229-242
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    • 2009
  • Numerical analysis has been performed to estimate maximum settlement, maximum horizontal displacement and total settlement volume at the ground surface due to tunnel excavation varying ground condition, tunnel depth and diameter, and construction condition (volume loss at excavation face). The maximum surface settlement from the numerical analysis has been compared with the maximum settlement at tunnel crown considering ground condition, tunnel depth and diameter, and construction condition, and it has been also compared with the maximum horizontal displacement. In addition, the volume loss ($V_L$) at tunnel excavation face has been compared with the total surface settlement volume ($V_s$) with the variation of ground condition, tunnel depth, and tunnel diameter. The results from the numerical analysis have been compared with field measurements to confirm the applicability and validity of the results and by this comparison it is believed that the numerical results in this study can be utilized practically in analyzing the ground movements due to tunnel excavation.

A study on the application of the critical strain concept by using the displacements occurring before excavation in tunneling (터널 선행변위를 활용한 한계변형률 개념의 적용 연구)

  • Park, Si-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.10 no.4
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    • pp.337-347
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    • 2008
  • Critical strain is a new material property of the ground. Critical strain concept which was established in tunnel engineering can be applied to deformation limits in the ground due to tunneling by using the measured displacement at the tunnel construction site. In this study, quantitative evaluations for the tunnel stability are conducted by analysing the displacement results obtained at the construction field. Especially, critical stain concept was reviewed from a total displacement point of view using the displacements occurring before excavation. As a results, the variation characteristics of the tunnel stability are presented on the critical strain diagram with or without the preceeding displacements.

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Estimation of Tunnel Convergence Using Statistical Analysis (통계처리를 활용한 터널 내공변위의 분석에 관한 연구)

  • 김종우
    • Tunnel and Underground Space
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    • v.13 no.2
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    • pp.108-116
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    • 2003
  • Measured convergence data of a tunnel were investigated by means of statistical and regression analysis, where the rock mass were mainly composed of andesite and granite. The rock mass around tunnel were classified by RMR method into five different ratings, and then convergence data which belong to individual ratings were statistically processed to find out the appropriate regression equations. Exponential equations were better coincided with measured data than logarithmic equations. As the number of rock mass rating was increased, the magnitude and standard deviation of convergence were increased. Final convergence data were also investigated to study the relevance with both maximum displacement rate and early measured convergence. Some brief results of their relevance are presented. For instance, the regression coefficient between final convergence and maximum displacement rate was turned out to be 0.87 for this studied tunnel.

Suggestion of a Modified RMR based on Effect of RMR Parameters on Tunnel Displacement in Sedimentary Rocks (퇴적암 기반 터널에서의 지질인자별 변위 영향도를 고려한 RMR 수정 제안)

  • Seo, Yong-Seok;Yim, Sung-Bin;Na, Jong-Hwa;Park, Si-Hyun
    • The Journal of Engineering Geology
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    • v.18 no.2
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    • pp.197-205
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    • 2008
  • Total displacement under non-reinforcement is a quantitative index of rock mass behavior during tunnel excavation and depends widely upon geological characteristics. The primary purpose of this study is to suggest a rock mass evaluation method, well representing tunnel behavior during excavation, according to rock type. A 3-D numerical analysis was carried out, with consideration of the shape of tunnel section, excavation condition and so forth, in a sedimentary rock-based tunnel, and total displacements under non-reinforcement according to rock mass class were calculated. Finally, quantification analysis was carried out to assess correlation of the total displacement with RMR parameters. As the result, a modified RMR system fer quantification of rock mass behavior during tunnel excavation is suggested.

Rock Displacement Measurement System by Precise Vision Metrology (정밀 화상계측법을 이용한 암반변위 계측시스템)

  • Hwang, Jae-Yun
    • Tunnel and Underground Space
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    • v.21 no.6
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    • pp.450-459
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    • 2011
  • For the purpose of evaluating the safety of rock structures such as underground caverns, tunnels and slopes, rock displacement measurement is carried out to identify the behavior of rock masses. Tapes, levels, and total stations are usually applied to the displacement measurement. These tools, however, are weighed down by many disadvantages. In this study, a new displacement measurement system by precise vision metrology was proposed for the observational design and construction method of rock structures, and then applied to a tunnel under construction. Comparisons and investigations of the measurement of the tunnel have confirmed the effectiveness and applicability of the developed measurement system.

Evaluation of surface displacement equation due to tunnelling in cohesionless soil

  • Mazek, Sherif A.
    • Geomechanics and Engineering
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    • v.7 no.1
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    • pp.55-73
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    • 2014
  • The theoretical predictions of ground movements induced by tunnelling are usually based on the assumptions that the subsoil has the same soil densities. The theoretical prediction does not consider the impact of different sand soil types on the surface settlement due to tunnelling. The finite elements analysis (FEA) considers stress and strength parameters of the different sand soil densities. The tunnel construction requires the solution of large soil-structure interaction problem. In the present study, the FEA is used to model soil-tunnel system performance based on a case study to discuss surface displacement due to tunnelling. The Greater Cairo metro tunnel (Line 3) is considered in the present study as case study. The surface displacements obtained by surface displacement equation (SDE) proposed by Peck and Schmidt (1969) are presented and discussed. The main objective of this study is to capture the limitations of the parameters used in the SDE based on the FEA at different sand soil densities. The study focuses on the parameters used in the SDE based on different sand soil densities. The surface displacements obtained by the FEA are compared with those obtained by the SDE. The results discussed in this paper show that the different sand soil densities neglected in the SDE have a significant influence on the surface displacement due to tunnelling.