Numerical analysis of the effect of bilateral excavation and superstructure loading on existing metro twin tunnels
Numerical analysis of the effect of bilateral excavation and superstructure loading on existing metro twin tunnels
The construction of a superstructure with a basement near the existing underground structure will redistribute the stresses around it. This paper aims to study the response of existing twin tunnels due to bilateral excavation and loading on either side of the tunnels. A parametric study was conducted numerically using the hardening soil model. The effects of the construction sequence of both the structures, symmetrical and unsymmetrical loading, foundation depth, number of floors, depth of the exist-ing tunnel, and horizontal offset distance were analyzed. Uplift deformation was observed during the excavation, while the opposite behavior was observed during the loading phase. During the excavation stage, the displacement at the spring levels is greater than the displacement at the crown, whereas, during the loading stage, the crown is more displaced than the spring levels. These displacements may lead to cracking and spalling of the lining and water seepage. The symmetry of the construction se-quence was observed to impact the tunnel's distortion significantly. The horizontal offset distance of the foundation has a signif-icant impact on the relative displacement of the tunnel.
Aryan S. Jajma; Vinay Kumar Singh; R. Ayothiraman
10th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE2023)
10. Tunnelling and mining applications
https://doi.org/10.53243/NUMGE2023-419
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