土木工程建筑外文翻譯外文文獻(xiàn)英文文獻(xiàn)地鐵地表沉降

1、 外文原文Surface settlement predictions for Istanbul Metro tunnelsexcavated by EPB-TBMS. G. Ercelebi ? H. Copur ? I. OcakAbstract In this study, short-term surface settlements are predicted for twin tunnels, which are to be

2、excavated in the chainage of 0 ? 850 to 0 ? 900 m between the Esenler and Kirazl? stations of the Istanbul Metro line, which is 4 km in length. The total length of the excavation line is 21.2 km between Esenler and Basak

3、sehir. Tunnels are excavated by employing two earth pressure balance (EPB) tunnel boring machines (TBMs) that have twin tubes of 6.5 m diameter and with 14 m distance from center to center. The TBM in the right tube fol

4、lows about 100 m behind the other tube. Segmental lining of 1.4 m length is currently employed as the final support. Settlement predictions are performed with finite element method by using Plaxis finite element program

5、. Excavation, ground support and face support steps in FEM analyses are simulated as applied in the field. Predictions are performed for a typicalgeological zone, which is considered as critical in terms of surface settl

6、ement. Geology in the study area is composed of fill, very stiff clay, dense sand, very dense sand and hard clay, respectively, starting from the surface. In addition to finite element modeling, the surface settlements a

7、re also predicted by using semi-theoretical (semi-empirical) and analytical methods. The results indicate that the FE model predicts well the short-term surface settlements for a given volume loss value. The results of

8、semi-theoretical and analytical methods are found to be in good agreement with the FE model. The results of predictions are compared and verified by field measurements. It is suggested that grouting of the excavation v

9、oid should be performed as fast as possible after excavation of a section as a precaution against surface settlements during excavation. Face pressure of the TBMs should be closely monitored and adjusted for different z

10、ones.Keywords Surface settlement prediction _ Finite element method _ Analytical method _ Semi-theoretical method _ EPB-TBM tunneling _ Istanbul MetroIntroductionIncreasing demand on infrastructures increases attention

11、to shallow soft ground tunneling methods in urbanized areas. Many surface and sub-surface structures make underground construction works very delicate due to the influence of ground deformation, which should be definit

12、ely limited/controlled to acceptable levels. Independent of theexcavations: (1) numerical analysis such as finite element method, (2) analytical method and (3) semi-theoretical (semi-empirical) method. Among them, the

13、 numerical approaches are the most reliable ones. However, the results of all methods should be used carefully by an experienced field engineer in designing the stage of an excavation project. In this study, all three pr

14、ediction methods are employed for a critical zone to predict the short-term maximum surface settlements above the twin tunnels of the chainage between 0 ? 850 and 0 ? 900 m between Esenler and Kirazl? stations of Istanbu

15、l Metro line, which is 4 km in length. Plaxis finite element modeling program is used for numerical modeling; the method suggested by Loganathan and Poulos (1998) is used for the analytical solution. A few different sem

16、i-theoretical models are also used for predictions. The results are compared and validated by field measurements.Description of the project, site and construction methodThe first construction phase of Istanbul Metro line

17、 was started in 1992 and opened to public in 2000. This line is being extended gradually, as well as new lines are being constructed in other locations. One of these metro lines is the twin line between Esenler and Basak

18、sehir, which is 21.2 km. The excavation of this section has been started in May 2006. Currently, around 1,400 m of excavation has already been completed. The region is highly populated including several story buildings,