In the past months, Marti Tunnelbau AG has mastered every challenge of the complex geology of the Belchen, using a TBM S-947. Consequently, 80% of the total length were reached in March, as planned.
The tunnel tube is being continuously secured with segment rings, simultaneously with the interior work. In a first step, the invert arch will be sealed by employees of Renesco AG, then the employees of Marti Tunnelbau AG will proceed with the reinforcement and the concrete. The prefabricated service tunnel elements will then be transferred onto the completed invert, then reinforced and back-filled. The following steps include the sealing, reinforcement and concreting of the arch. The final phase consists of the mounting of the intermediate ceiling, which has been covering the first 800m since the start in November.
If the construction works continue to proceed according to the plan, the tunnel boring machine will reach the northern portal in Eptingen in the Basel region in July. The breakthrough will be adequately celebrated.