| Macro-simulation of fluid flow and the interaction with the excavation process of the Brenner Base Tunnel Konrad Bergmeistser1; Tassilo Weifner2; 1, Vienna, Austria; 2BRENNER BASE TUNNEL BBT SE, Innsbruck, Austria; PAPER: 465/Geomechanics/Invited (Oral) SCHEDULED: 17:50/Fri. 25 Oct. 2019/Athena (105/Mezz. F) ABSTRACT: The tunnel track of the Brenner Base Tunnel crosses the base of the Brenner Massif passing through an important aquifer in the Hochstegen zone, which shows an essential influence on the water balance on the ground surface. In order to investigate the hydrological situation before and after the tunnel construction, two-dimensional models of the groundwater flow system with the finite difference code MODFLOW were produced. The scope of these models was on one hand to obtain information about the effects of the drawdown of the groundwater table by the draining effect during the tunnel excavation. On the other hand, an intention of the model was to investigate whether the drawdown of the groundwater table could be kept to a small and acceptable extent through suitable grouting measures and thus keep the influence on the groundwater balance in the model area low. The calculations show that the drawdown of the groundwater table in the zone of the aquifer of the Hochstegen Zone can be reduced to a small, acceptable extent. A drilling campaign with pumping tests was in execution and gave already additional input data. The paper deals with the model, the hydraulic parameters, the data from grouting measures obtained in other deep tunnel projects and from the drilling campaign and their effects on the modelling parameters and describes in detail the knowledge gained. References: Weifner, T.; Bergmeister, K.; Ziegler H.: Wide-area hydrogeological modelling for the Brenner Base Tunnel. Geomechanics and Tunneling. Ernst & Sohn, 1014-4, pag. 163-77 |
