Open Access

ARTICLE

Impact of Overhead Excavation on an Existing Shield Tunnel: Field Monitoring and a Full 3D Finite Element Analysis

F. Wang^1,2, D.M. Zhang^1,2,3, H.H. Zhu⁴, H.W. Huang^1,2, J.H. Yin⁵

1 Key Laboratory of Geotechnical and Underground Engineering of Minister of Education, Tongji University, Shanghai 200092, China.
2 Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China.
3 Corresponding author
4 School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China.
5 Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hong Kong, China.

Computers, Materials & Continua 2013, 34(1), 63-81. https://doi.org/10.3970/cmc.2013.034.063

Abstract

This paper studies the impact of overhead excavation on an existing tunnel through both field monitoring and a full 3D numerical model. It is found that the excavation induced longitudinal heave of the tunnel is uneven with maximum heave occurring below the excavation center. Even at the same cross section, the excavation induced heave is not uniform with the most significant heave occurring at the tunnel crown. The bending moments of the tunnel lining is decreased due to the overhead excavation. The axial forces of the tunnel lining generally decrease except at the tunnel invert. The shear forces of the tunnel increase substantially. The excavation induced tunnel deformation and internal forces may reduce the effectiveness of the waterproof system.

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Keywords

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