Tunnel waterproofing in Campania

Avellino is located in Italy’s Campania region, some 40 km east of Naples. And it is here that the “Galleria Giglio” lies along the Benevento – Codola rail route. The tunnel, almost 160 metres long, 5 metres wide and featuring a pointed arch and masonry shoulders, was built in the 1930s. Having fallen into some considerable disrepair, the structure urgently needed to be sealed, as groundwater was already pushing through the walls from the sides and significant surface water was penetrating from above through the bricks of the ceiling. Although there is no overhead line installed in the tunnel to complicate matters, the ingress of water and the falling bricks loosened by the moisture had damaged both the fabric of the structure and the rails, thus endangering rail traffic.
Thermit S.R.L., based in Naples, was commissioned to carry out the waterproofing work, with MC's know-how input very much part of the project. Working together with Ricardo Quiroz, Business Development Manager at MC, and Markus Treinen, Global Target Manager Injection, Thermit was able to develop a waterproofing system tailored to the job in hand.
Watertight solution

This consisted of a curtain injection seal using MC-Injekt GL-95 TR, a soft elastomeric hydro-structural resin. With its low viscosity and brief, controllable reaction, it offered the twin benefits of exceptional penetration into the masonry and rapid sealing. MC-Injekt GL-95 TR has been specifically developed both for the injection-based waterproofing of masonry and concrete with permanent water contact and as a secondary horizontal or vertical repair barrier to prevent penetrating moisture in masonry.

Its elasticity also ensures that the tunnel in Avellino remains sealed despite the movement generated by rail traffic. A further key factor for the customer was that the hydro-structural resin is approved for waterproofing barriers in contact with groundwater.
Injection work with operations ongoing

The injection work began on 26 August 2018 and was carried out on the basis of a 50 x 50 cm grid with a depth of 30 cm and a diameter of 18 mm per hole. About 6 kg of the special resin was injected per hole. MC-Injekt GL-95 TR is compatible with old masonry structures and can even be applied where space is tight. As a consequence, there was no need to stop rail traffic passing through the tunnel. Instead, the work was shifted to night time when train frequency was light, with the results then being inspected during the day. The waterproofing project was successfully completed in just three weeks, since when rail traffic has been travelling through Avellino’s Galleria Giglio without disruption or danger.