Three dimensional structural response of segmental tunnel linings

The particular configuration of segmental tunnel linings produces that its structural response in front of usual design loads could present a significant three dimensionality due to the structural interaction between adjacent rings (coupling effects). The present paper studies the phenomena associated to coupling effects, determines the main involved parameters and analyzes their influence on a real lining structural response by means of a 3D numerical model. The comparison with the usual plane models currently employed in linings designs provide significant conclusions about the coupling effects implications and the conditions in which become more relevant.

► Analysis of ring interaction mechanisms when lining is subjected to design loads.
► Significant increases of lining stiffness caused by so called coupling effects.
► Influence zone determined by soft ground conditions and high ovalization loads.
► Coupling can produce increments of the internal bending forces over 150%.
► Recommendations about usual design practices based on isolated ring models.