Simulation Analysis of A Metro Station Construction in Shenzhen with Small TBM Advancing Excavation Followed by Large TBM Enlargement

Autor: Hong LI, Lei KE, Xuanying LI, Hao ZHOU, Bo XIAO, Jiaolong ZHANG
Jazyk: čínština
Rok vydání: 2024
Předmět:
Zdroj: Chengshi guidao jiaotong yanjiu, Vol 27, Iss 3, Pp 92-96 (2024)
Druh dokumentu: article
ISSN: 1007-869X
1007-869x
DOI: 10.16037/j.1007-869x.2024.03.017.html
Popis: [Objective] The new technique of small-diameter TBM (tunnel boring machine) advancing excavations followed by large-diameter TBM enlargement is used for the first time in the construction of Tumor Hospital Station on Shenzhen Metro Line 14. As the geological stability is hard to be predicted when the large diameter TBM advances in the artificial composite geological stratum, which is back-filled after the small diameter TBM excavation, it is necessary to simulate and analyze the station built with such construction technique. [Method] MIDAS/GTS software is used to simulate the effect of different backfill materials and buried depths on ground settlement and on the stress of the segment structure when the excavation of the large shield tunnel and the construction of support structure are completed. [Result & Conclusion] The analysis results show that when C40 concrete, C15 concrete and muck are respectively used as backfill materials, the stratum displacement and the maximum stress of the segment structure caused by the large excavation are increasing with the strength of the backfill material decreasing. When C15 and C40 concrete are used as backfill materials, the shield tunneling has no much effect on the surrounding rocks and geological stratum. C15 concrete is recommended as the backfill material for this project. It is highly risky that the large TBM directly drives the tunnel which is not backfilled after the small TBM tunneling. Ground settlement is insignificant when the buried depth ranges from 21 m to 45 m. But following the deepened buried depth, the ground stress increases significantly, and so does the stress of the tunnel structure.Tumor Hospital Metro Station on Shenzhen Metro Line 14 adopts the C15 concrete backfilling plan in the end, and the monitoring results of ground settlement is basically in line with the numerical simulation calculation.
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