An application of confined concrete modeling to three-dimensional nonlinear finite element analysis: The example of tunnel boring machine lining joints

摘要

The aim of this paper is to present through a practical example, some recommendations to properly model confined concrete in three-dimensional nonlinear finite element analysis. The example chosen is of particular interest for tunneling and structural engineers as it compromises the joints between segments of the concrete lining used with the tunnel boring machine technique. These sections are designed to transmit high pressures, sometimes exceeding the Standards' recommendations. To carry out the nonlinear finite element analyses (NLFEAs) a dedicated software, was employed. A discussion about which parameters play a fundamental role to efficiently model the problem is carried out. Finally, a comparison between NLFEA results and an experimental campaign is presented highlighting the differences in terms of stress values within the steel bars, the failure mechanism and evaluation of the contribution of steel to the resistance of confined concrete.