A geological fault zone in the Grassberg during the drive in Gloggnitz makes an extension of the construction time inevitable, the ÖBB announced on Friday. According to the company, the technical challenges, in combination with rising costs for building materials and energy, are leading to an increase in the project volume from the previously estimated EUR 3.5 billion to EUR 3.9 billion.
The new schedule is based on “detailed evaluation of the structural, technical and geological aspects of the major project,” it said in a broadcast. The prognosis that the special measures in the Grassberg area decided on and then implemented in the previous year would comprehensively solve the technical and geological challenges was not fulfilled. It was now clear that further steps had to be taken. “Here is an extremely complicated mountain structure, which is characterized by completely different rock layers,” it was emphasized.
The previous injection measures in the affected construction section are now being extended. This happens “until a stable crossing of the fault zone can be carried out safely using excavators and blasting”.
Around 23 of the total of 27.3 kilometers of the twin-tube tunnel have already been dug, the ÖBB calculated. The SBT is being excavated from five locations and 14 simultaneous drives, four of the drives (all in the Fröschnitzgraben) have already been completed.
In 2020, the so-called interior work on the tunnel tubes also started. These are lined with a concrete inner shell. The final step is the railway equipment with tracks, lines and technical systems.
Source: Nachrichten
