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Quantitative Analysis of the Factors Affecting the Face Instability of
a River-Crossing Shield Tunnel of the Nanjing Metro
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Quantitative Analysis of the Factors Affecting the Face Instability of
a River-Crossing Shield Tunnel of the Nanjing Metro
(1 State Key Laboratory for Explosion & Impact and Disaster Prevention & Mitigation, PLA University of Science and Technology, Nanjing 210007; 2 Nanjing Subway Co. Ltd., Nanjing 210007)
Abstract By way of systematic analysis of the risk factors resulting in instability of the tunnel face during shield construction, it was found that large deviation of the slurry pressure from the actual lateral static water-soil pressure is the main reason for large settlement or collapse at the working face. The concept of an ultimate support stress ratio and the judgment criteria for instability are presented and a quantitative description concerning the factors affecting the stability of the tunnel face is carried out. Using the river-crossing tunnel of the Nanjing Metro line 10 as an example, the affects of buried depth, river depth, and soil parameters (cohesion, internal friction angle) on the instability of the working face are studied by a Mohr-Coulomb model, which is commonly used in geotechnical engineering, and a 3D numerical analysis method. Considering the river water, the influence of varied groundwater head heights is also studied.
Abstract：
By way of systematic analysis of the risk factors resulting in instability of the tunnel face during shield construction, it was found that large deviation of the slurry pressure from the actual lateral static water-soil pressure is the main reason for large settlement or collapse at the working face. The concept of an ultimate support stress ratio and the judgment criteria for instability are presented and a quantitative description concerning the factors affecting the stability of the tunnel face is carried out. Using the river-crossing tunnel of the Nanjing Metro line 10 as an example, the affects of buried depth, river depth, and soil parameters (cohesion, internal friction angle) on the instability of the working face are studied by a Mohr-Coulomb model, which is commonly used in geotechnical engineering, and a 3D numerical analysis method. Considering the river water, the influence of varied groundwater head heights is also studied.
.Quantitative Analysis of the Factors Affecting the Face Instability of
a River-Crossing Shield Tunnel of the Nanjing Metro[J] MODERN TUNNELLING TECHNOLOGY, 2013,V50(5): 112-117
2013, Vol. 50 