• Title, Summary, Keyword: 최종내공변위

Search Result 11, Processing Time 0.033 seconds

Relations between Initial Displacement Rate and Final Displacement of Arch Settlement and Convergence of a Shallow Tunnel (저심도 터널의 천단침하 및 내공변위의 초기변위속도와 최종변위의 관계)

  • Kim, Cheehwan
    • Tunnel and Underground Space
    • /
    • v.23 no.2
    • /
    • pp.110-119
    • /
    • 2013
  • It is generalized to measure the arch settlement and convergence during tunnel construction for monitoring its mechanical stability. The initial convergence rate a day is defined from the first convergence measurement and the final convergence defined as the convergence measured lastly. The initial and the final tunnel arch settlement are defined like the preceding convergence. In the study, the relations between the initial and final displacements of a shallow tunnel are analyzed. The measurements were performed in the tunnel of subway 906 construction site in Seoul. The overburden is 10-20 m and the tunnel goes through weathered soil/rock. The width and height of the tunnel are about 11.5 m, 10m, respectively. So this is a shallow tunnel in weak rock. The length of tunnel is about 1,820 m and the tunnel was constructed in 2 stages, dividing upper and lower half. The numbers of measurement locations of arch settlement and convergence are 184 and 258, respectively. As a result, the initial displacement rate and the final displacement are comparatively larger in the section of weathered soil.

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

  • 김종우
    • Tunnel and Underground Space
    • /
    • v.13 no.2
    • /
    • pp.108-116
    • /
    • 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.

A study on the relationship between initial and final convergence in NATM tunnels (NATM 터널 굴착시 초기 내공변위와 최종 내공변위의 상관관계 연구)

  • Kim, Bum-Joo;Hwang, Young-Cheol
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.10 no.3
    • /
    • pp.233-243
    • /
    • 2008
  • A tunnel behavior predicted in the investigation and design stage is often different from its actual behavior due to mainly the complexity of ground conditions. In a tunnel construction, therefore, it is necessary to ensure the stability of the tunnel by predicting the behaviors of the ground and the supports through observations and measurements, and modifying immediately excavation and reinforcing methods when necessary. To do so, it is important to be able to predict the final tunnel behavior based on the initial tunnel behavior as early as possible. In this study, the correlations were obtained between the initial and the final convergence by analyzing statistically the convergence measurement data, collected from two domestic road tunnels under construction using NATM. In order to estimate the unknown displacements, occurred during the period between the excavation and the first measurement, two methods were used - one is the method by means of regression analysis using a modified exponential function and the other the method by a simple linear regression analysis using the data measured within the distance from tunnel face equal to the tunnel diameter (D). Finally, the relationships were obtained between the initial and final convergence, including the non-measured displacements estimated from the two different methods, by performing linear regression analyses. The regression analysis results showed that there are clear linear relationships between the initial and final convegence and the difference between the two linear regression equations was not that large for when using the exponential function and the simple linear function to estimate the non-measured displacements.

  • PDF

Forecasting Final Displacement With Displacement Functions Using Deformation Measurements While Constructing a Tunnel (계측치와 변위함수에 의한 시공 중인 터널의 최종변위 예측)

  • Kim, Chee-Hwan
    • Tunnel and Underground Space
    • /
    • v.20 no.6
    • /
    • pp.408-420
    • /
    • 2010
  • It is important to forecast the final deformation of a tunnel during construction for evaluating its mechanical stability. In this study, the final deformation of a tunnel is forecasted by fitting tunnel deformations measured while excavating to a displacement function and exterpolating it. The tunnel for the study was built in two stages divided into an upper and a lower part. During the lower part construction of the tunnel, the displacement function forecasts the final incremental displacement well compared to the increment measured after completion of the tunnel. It is because the critical initial displacement occurred on passing the measurement pins can be adequately measured during excavating the lower part, which can not be measured during the upper part excavation of the tunnel.

초기계측치를 이용한 경암 지반내 터널의 최종변위량 예측

  • 송승곤;양형식;임성식;정소걸
    • Proceedings of the Korean Society for Rock Mechanics Conference
    • /
    • /
    • pp.37-44
    • /
    • 2002
  • 터널의 초기 변형결과를 역해석에 적용하기 위하여 초기 값들과 최종변위의 상관관계를 연구하였다 Panet의 지수함수와 분수함수는 경암 터널의 내공변위 예측에 잘 맞았다. ID지점의 초기 계측변위는 선형적으로 적합시킬 수 있으나 계측 전 변형의 추정식으로는 부적합하였다. 초기 계측 결과들과 최종 변형결과는 선형적인 비례관계를 보였으며 이로써 초기 계측결과로부터 추정한 최종변형치를 이용한 역해석이 가능함을 보였다.

  • PDF

Estimation of Final Deformation of Hard Rock Tunnel Using Early Measured Deformation (초기계측치를 이용한 경암 지반내 터널의 최총변위량 예측)

  • 송승곤;양형식;임성식;정소걸
    • Tunnel and Underground Space
    • /
    • v.12 no.2
    • /
    • pp.99-106
    • /
    • 2002
  • To use the early measured data of tunnel deformation in but analysis, the relationship between these values find final deformation data were studied. Panet\`s exponential and fraction equations successfully approximate the convergence of the hard rock tunnels. Measured deformation data of ID location, $U_{1D}$ show that they can be lilted to linear equations but should not be used to estimate potential deformation before measurement, $C_{0}$. Early measured data $U_{1D}$ $U_{2D}$ , and final deformation $ U_{L}$ showed linear correlations. It proved that estimated data of final deformation from early measured ones can be used as input parameters for back analysis.

A Numerical Analysis Study for the Prediction of Convergences and Characteristics of Subsidence behavior in Shallow, Wide Tunnel Excavation (천층 광폭터널의 내공변위 및 침하거동특성 예측을 위한 수치해석적 연구)

  • 문승백;송승곤;양형식;전양수;한공창
    • Tunnel and Underground Space
    • /
    • v.11 no.1
    • /
    • pp.20-29
    • /
    • 2001
  • Final convergence of tunnel crown due to excavation have been well predicted by regression analysis which is expressed as a function of convergence curve on a time and distance dependent. In this study, the validity of the equations for shallow, wide tunnel was investigated by measurement and numerical analysis. Studied tunnel(Sansoo Tunnel) is located at the boundary of downtown and mountain park. Exponential predictions equation was better coincided with measured data than fractional equation for studied tunnel, although the ground was expected to be elasto-plastic. This is because weathered rock ground is changed elasto-plastic ground into elastic ground by multi-steel grouting and forepoling.

  • PDF

Prediction of a Fault Zone ahead of a Tunnel Face based on the Orientation of Displacement Vectors (변위벡터방향성을 이용한 터널 전방 단층대 예측에 관한 연구)

  • Kim, Kwang-Yeom;Yim, Sung-Bin;Kim, Jang-Kyeom;Seo, Yong-Seok;Kim, Jin-Woung
    • The Journal of Engineering Geology
    • /
    • v.20 no.4
    • /
    • pp.371-380
    • /
    • 2010
  • A three-dimensional finite element analysis was performed to predict the location of a fault zone ahead of a tunnel face based on convergence displacement. Geometrical models for the numerical analysis were developed based on the possible geometric intersection between the fault zone and the tunnel. Fifteen fault models were generated from combinations of faults with five different strikes (at $15^{\circ}$ intervals) and three dips (vertical, $45^{\circ}$ and $-45^{\circ}$) relative to the tunnel route. The displacements on the crown and side walls were calculated and analyzed using a vector orientation approach. As a result, nine representative prediction charts were developed, showing location and orientation of the fault zone based on convergence displacement.

Longitudinal Deformation Profile in Tunnel using Measured Data (계측자료를 이용한 터널의 종단변형도)

  • Jang, Won-Yil;Yang, Hyung-Sik;Chung, So-Keul
    • Tunnel and Underground Space
    • /
    • v.18 no.5
    • /
    • pp.338-342
    • /
    • 2008
  • Longitudinal deformation profile(LDP) has been obtained mostly by numerical analysis. In this study, LDP was plotted by measured data from horizontal inclinometer and crown settlement. Deformation of foe ahead was determined by comparing to the maximum deformation point and deformation of after excavation was determined by regression of the measured crown settlement data. The result shows that crown deformation began as f3r as 3D ahead of the face. Crown settlement at the face was 40% of ultimate deformation, which was 10% higher than numerical results, and the deformation converged after excavation of 4D.

Back Analysis of Field Measurements Around the Tunnel with the Application of Genetic Algorithms (유전자 알고리즘을 이용한 터널 현장 계측 결과의 역해석)

  • Kim Sun-Myung;Yoon Ji-Sun;Jun Duk-Chan;Yoon Sang-Gil
    • Journal of the Korean Geotechnical Society
    • /
    • v.20 no.7
    • /
    • pp.69-78
    • /
    • 2004
  • In this study, the back analysis program was developed by applying the genetic algorithm, one of artificial intelligence fields, to the direct method. The optimization process which has influence on the efficiency of the direct method was modulated with genetic algorithm. On conditions that the displacement computed by forward analysis for a certain rock mass model was the same as the displacement measured at the tunnel section, back analysis was executed to verify the validity of the program. Usefulness of the program was confirmed by comparing relative errors calculated by back analysis, which is carried out under the same rock mass conditions as analysis model of Gens et at (1987), one of back analysis case in the past. We estimated the total displacement occurring by tunnelling with the crown settlement and convergence measured at the working faces in three tunnel sites of Kyungbu Express railway. Those data measured at the working face are used for back analysis as the input data after confidence test. As the results of the back analysis, we comprehended the tendency of tunnel behaviors with comparing the respective deformation characteristics obtained by the measurement at the working face and by back analysis. Also the usefulness and applicability of the back analysis program developed in this study were verified.