Design Improvements of Segmental Linings Due to Unfavorable Bedding Situations

With mechanized shield tunnelling the quality of the backfill is of significant importance for the stability of the lining. The used material affects the interaction between support and rock mass. Therefore, the choice of a proper backfilling material is of great importance for the system behaviour....

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Bibliographic Details
Published in:Procedia engineering 2017, Vol.191, p.729-734
Main Authors: Henzinger, M.R., Pejic, D., Schubert, W.
Format: Article
Language:English
Subjects:
bedding
mortar
pea gravel
segmental lining
TBM
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Summary:With mechanized shield tunnelling the quality of the backfill is of significant importance for the stability of the lining. The used material affects the interaction between support and rock mass. Therefore, the choice of a proper backfilling material is of great importance for the system behaviour. Scaled model tests have shown the relocation behaviour of pea gravel within the annular gap. The tests have shown that especially with Double shielded TBMs a distinct relocation mechanism is triggered by the regripping process. This leads to an unfavourable bedding situation immediately behind the TBM shield. Based on a concept study two design improvements have been developed to improve the bedding situation. The first one is based on using geotextile tubes around the lining segments which also prevents a large-scale relocation process of pea gravel within the annular gap. The basic idea of the second concept is the use of ductile support elements with yielding potential in radial direction. Both systems solely differ in the fixation leading to different load cases of the lining. Due to the clamping mechanism, the forces acting on the yield elements are transformed into indirect tensile stresses around the element within the lining.
ISSN:1877-7058
1877-7058
DOI:10.1016/j.proeng.2017.05.238