Abstract Improper construction of underground structures could have a huge impact on the structure of adjacent existing metro shield tunnels. Based on a large deformation case occurring in an existing operational metro shield tunnel caused by the under-passing construction of a certain Guangzhou metro tunnel section, this paper analyzes the mechanical conditions of the segment structure under different ovality deformations of the existing tunnel structure caused by ground loss. Based on measured engineering data, and using the three-dimensional finite element analysis software, this paper studies the quantitative relationship between the ovality of the segment ring and the stress state of the structure, and analyzes the plastic deformation of the structure and its development trend, considering detailed structures such as the bolt holes at the segment joints. The results show that the maximum principal stress value and the maximum shear stress value of the structure increase with the rise in the ovality of the shield tunnel segment ring, and the maximum shear stress of the shield tunnel structure shows a linear relationship with the degree of ovality; the maximum principal stress of the shield tunnel structure varies more significantly with the degree of ovality, showing a non-linear relationship.
Abstract：
Improper construction of underground structures could have a huge impact on the structure of adjacent existing metro shield tunnels. Based on a large deformation case occurring in an existing operational metro shield tunnel caused by the under-passing construction of a certain Guangzhou metro tunnel section, this paper analyzes the mechanical conditions of the segment structure under different ovality deformations of the existing tunnel structure caused by ground loss. Based on measured engineering data, and using the three-dimensional finite element analysis software, this paper studies the quantitative relationship between the ovality of the segment ring and the stress state of the structure, and analyzes the plastic deformation of the structure and its development trend, considering detailed structures such as the bolt holes at the segment joints. The results show that the maximum principal stress value and the maximum shear stress value of the structure increase with the rise in the ovality of the shield tunnel segment ring, and the maximum shear stress of the shield tunnel structure shows a linear relationship with the degree of ovality; the maximum principal stress of the shield tunnel structure varies more significantly with the degree of ovality, showing a non-linear relationship.
DING Xiaobin HAN Donglin
.Analysis of Mechanical Performance of Operational Shield Tunnels under Different Ovality Deformations[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(1): 141-148
2022, Vol. 59 