Brennero tunnel

DETAILS OF THE WORK

Consorzio Brennero 2011 entrusted ASACERT with the task of carrying out the technical control activity during construction in relation to the construction of the exploratory tunnel of the Brenner Base Tunnel and the related preparatory works.

The Brenner Tunnel represents one of the most ambitious civil engineering projects of recent years: once completed it will constitute the longest underground railway connection in the world, with a length of 64 km including the Innsbruck ring road, and will directly connect the city Italian Fortezza (BZ) with Austrian Innsbruck. Once completed, the project – whose excavations began in 2007 and should end in 2026 – will have a key strategic value for the freight transport sector; the possibility of exploiting the direct railway connection, in fact, will allow us to increase the percentage of transport carried out by rail, increasing performance, speed and safety and significantly reducing pollution levels in the area.

The exploratory tunnel is part of the complex system of secondary tunnels that flank the Brenner Tunnel; it extends along the entire area of interest and is positioned under the main tunnels at a distance of 12 m. The exploratory tunnel has a fundamental importance for the success of the work, during the construction and excavation phase it has two main functions:

• Cognitive function: provides information and geological data that are difficult to find a priori
• Logistics function: allows the transport of materials and machinery during construction.

At the end of the tunnel construction work, the exploratory tunnel will be used for maintenance and water drainage.

SERVICE

ASACERT carried out the technical control service during construction – with a total cost of the works equal to approximately €70,000,000 – for the Brenner Tunnel lot relating to the preparatory works of the Mules construction site and the related exploratory tunnel in the section of crossing of the Periadriatic line, with specific reference to:

• Section of exploratory tunnel equal to 1544 m in length
• Preparatory works in the Mules area, including connection tunnels, line tunnels and connection tunnels, transverse tunnels, TBM assembly rooms, logistics rooms and ventilation shaft. The preparatory works extend for approximately 200 m in the south direction and 1800 m in the north direction of the connection point, as well as near the entrance to the Mules window.

ASACERT’s verification examined the requirement of stability and mechanical resistance of the structural elements, aimed at guaranteeing the prevention of total or partial ruin of the work and serious construction defects. The technical control was carried out by an ASACERT inspection group, made up of expert technicians with many years of experience, in conjunction with the design and construction phases of the works.

During the design phase, ASACERT carried out a careful examination of the project documentation, followed, during the construction phase, by carrying out sampling checks on the various fundamental and critical structural elements for the structural solidity of the work.

RESULT

In light of the documentary analyzes and surveys conducted on site, ASACERT expressed a positive opinion in reference to the stability and mechanical resistance of the parts of the work subject to the control. In fact, taking into account the complexity of the design in question, due to the unpredictability of the actual behavior of the rock masses crossed by the excavation, ASACERT deemed both the design and the construction of the exploratory tunnel compliant with the technical regulations in force and with the indications of good design technique and executive.