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Influence of the Approaching Construction of Underlying Shield Tunnels on Overlying Metro Tunnels
(1 Guangzhou Municipal Engineering Design & Research Institute, Guangzhou 510060; 2 School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510641)
Abstract The effects of shield tunnelling on adjacent buildings have long been a serious problem. In this paper, the approaching construction of an underlying shield tunnel was simulated by the finite element method and the displacement variation law of the existing metro tunnel during construction of the underlying shield tunnel was analyzed. Based on the double-sided elastic foundation beam theory and the shield tunnel longitudinal equivalent continuous model, a calculation equation for the segment openings of the existing metro tunnel affected by construction of the new shield tunnel was deduced and the distribution law for the segment openings was analyzed. The analysis results show that: 1) the area of the overlying, obliquely crossing metro tunnel affected by shield tunnel construction is mainly located in the range of 2D (D=tunnel diameter) on both sides of the new shield tunnel axis; 2)the vertical displacement distribution of the existing metro tunnel is mainly within the range of 2D ahead of the working face and 1.5D behind the shield tail; 3) the segment opening of the existing metro tunnel appears obviously at the two joints(left and right) directly above new the shield tunnel axis and is accompanied by plastic deformation; and 4) the area within 2D of the sides of the existing metro tunnel and the soil layer between the two tunnels should be locally reinforced to prevent longitudinal deformation and excessive segment opening of the existing metro tunnel associated with the new shield tunnelling.
Abstract：
The effects of shield tunnelling on adjacent buildings have long been a serious problem. In this paper, the approaching construction of an underlying shield tunnel was simulated by the finite element method and the displacement variation law of the existing metro tunnel during construction of the underlying shield tunnel was analyzed. Based on the double-sided elastic foundation beam theory and the shield tunnel longitudinal equivalent continuous model, a calculation equation for the segment openings of the existing metro tunnel affected by construction of the new shield tunnel was deduced and the distribution law for the segment openings was analyzed. The analysis results show that: 1) the area of the overlying, obliquely crossing metro tunnel affected by shield tunnel construction is mainly located in the range of 2D (D=tunnel diameter) on both sides of the new shield tunnel axis; 2)the vertical displacement distribution of the existing metro tunnel is mainly within the range of 2D ahead of the working face and 1.5D behind the shield tail; 3) the segment opening of the existing metro tunnel appears obviously at the two joints(left and right) directly above new the shield tunnel axis and is accompanied by plastic deformation; and 4) the area within 2D of the sides of the existing metro tunnel and the soil layer between the two tunnels should be locally reinforced to prevent longitudinal deformation and excessive segment opening of the existing metro tunnel associated with the new shield tunnelling.
.Influence of the Approaching Construction of Underlying Shield Tunnels on Overlying Metro Tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2015,V52(5): 145-151
2015, Vol. 52 