Filling material is present around the segment lining when a shielded Tunnel Boring Machine is used to excavate a tunnel. The two-component grout is becoming lately one of the most used filling materials. Its mechanical properties evolve over time. Unfortunately, there are not many studies in the literature on the specific mechanical characteristics of these materials. This work presents the results obtained from an extensive laboratory test campaign that allowed to fully characterize the two-component filling material during the setting period. In particular, the values of the stiffness and resistance parameters were obtained over time, where uniaxial compression tests and oedometer tests were carried out. A detailed study of the effect of the presence of the filling material on the behavior of the support system (segmental lining + filling material) was developed for two of the most widespread analytical methods for the analysis of the behavior of tunnels and structures of support: the convergence-confinement method and the Einstein and Schwartz method. Subsequent parametric analyses made it possible to consider the variability of the influencing parameters within the typical variability ranges obtained from the laboratory test campaign or known from the available scientific literature. From the study carried out, it was possible to note that it is necessary to consider the presence of the filling material in the evaluation of the stiffness of the support system, when using the convergence-confinement method to estimate the loads acting on segmental lining. In this regard, it is necessary to have a reliable estimate of the elastic modulus of the filling material in the period of loading of the segmental lining. On the other hand, the presence of the ring of filling material is negligible when evaluating the state of stress of the segmental lining with specific methods capable of considering the rock-support interaction. In particular, adopting the Einstein and Schwartz method, it is possible to define the bending moments and normal forces acting in the support structure, referring to the stiffness parameters of the segmental lining alone.
The influence of the two-component grout on the behaviour of a segmental lining in tunnelling / Oggeri, Claudio; Oreste, Pierpaolo; Spagnoli, Giovanni. - In: TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY. - ISSN 0886-7798. - STAMPA. - 109(2021).
|Titolo:||The influence of the two-component grout on the behaviour of a segmental lining in tunnelling|
|Data di pubblicazione:||2021|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.tust.2020.103750|
|Appare nelle tipologie:||1.1 Articolo in rivista|