Limits...
Analysis of face stability during excavation of Double-O-Tube shield tunnel.

Yang Y, Zhou Q, Li H, Huang X, Tu X - ScientificWorldJournal (2013)

Bottom Line: This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment.Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided.This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata.

View Article: PubMed Central - PubMed

Affiliation: School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, China.

ABSTRACT
This paper focuses on the face stability analysis of Double-O-Tube shield tunnel. This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment. The key point of the stability analysis is to determine the supporting pressure applied to the face by the shield. A collapse failure will occur when the supporting pressure is not sufficient to prevent the movement of the soil mass towards the tunnel. A three-dimensional collapse failure mechanism was presented in this paper. Based on the mechanism of a single circular shield tunnel, the mechanism of Double-O-Tube shield tunnel was established by using the fact that both of the mechanisms are symmetrical. Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided. The finite difference software FLAC3D was applied to investigate the face failure mechanism of DOT shield tunnel established in this paper; the critical supporting pressures of the collapse failure mechanism in different strata (sand and silt) were calculated. Through comparative analysis, the theoretical values were very close to the numerical values. This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata.

Show MeSH
The longitudinal ground settlements ahead of tunnel face after collapse failure of the tunnel face.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3794543&req=5

fig10: The longitudinal ground settlements ahead of tunnel face after collapse failure of the tunnel face.

Mentions: In order to investigate the ground settlement after the destruction of the tunnel face, the longitudinal and transverse subsidence monitoring points were laid on the ground surface in front of tunnel face. Figure 10 shows the longitudinal ground settlements after the face collapse failure occurs. The figure shows that there is a V-shaped settlement trough in sand strata after the face collapse failure of the DOT shield tunnel occurs. However, there is a U-shaped settlement trough in silt strata after the face collapse failure of the DOT shield tunnel occurs; the maximum settlement occurs in the front side about 3 m of tunnel face (approximately D/2; D is the diameter of the tunnel). The maximum ground settlement value in the sand strata is greater than that in the silt strata; however, the sphere of influence on the ground in the sand strata is smaller than in the silt strata.


Analysis of face stability during excavation of Double-O-Tube shield tunnel.

Yang Y, Zhou Q, Li H, Huang X, Tu X - ScientificWorldJournal (2013)

The longitudinal ground settlements ahead of tunnel face after collapse failure of the tunnel face.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3794543&req=5

fig10: The longitudinal ground settlements ahead of tunnel face after collapse failure of the tunnel face.
Mentions: In order to investigate the ground settlement after the destruction of the tunnel face, the longitudinal and transverse subsidence monitoring points were laid on the ground surface in front of tunnel face. Figure 10 shows the longitudinal ground settlements after the face collapse failure occurs. The figure shows that there is a V-shaped settlement trough in sand strata after the face collapse failure of the DOT shield tunnel occurs. However, there is a U-shaped settlement trough in silt strata after the face collapse failure of the DOT shield tunnel occurs; the maximum settlement occurs in the front side about 3 m of tunnel face (approximately D/2; D is the diameter of the tunnel). The maximum ground settlement value in the sand strata is greater than that in the silt strata; however, the sphere of influence on the ground in the sand strata is smaller than in the silt strata.

Bottom Line: This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment.Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided.This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata.

View Article: PubMed Central - PubMed

Affiliation: School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, China.

ABSTRACT
This paper focuses on the face stability analysis of Double-O-Tube shield tunnel. This kind of analysis is significant to ensure the safety of workers and reduce the influence on the surrounding environment. The key point of the stability analysis is to determine the supporting pressure applied to the face by the shield. A collapse failure will occur when the supporting pressure is not sufficient to prevent the movement of the soil mass towards the tunnel. A three-dimensional collapse failure mechanism was presented in this paper. Based on the mechanism of a single circular shield tunnel, the mechanism of Double-O-Tube shield tunnel was established by using the fact that both of the mechanisms are symmetrical. Then by means of the kinematic theorem of limit analysis, the numerical results were obtained, and a design chart was provided. The finite difference software FLAC3D was applied to investigate the face failure mechanism of DOT shield tunnel established in this paper; the critical supporting pressures of the collapse failure mechanism in different strata (sand and silt) were calculated. Through comparative analysis, the theoretical values were very close to the numerical values. This shows that the face failure mechanism of DOT shield tunnel is reasonable, and it can be applied to the sand and silt strata.

Show MeSH