Damage to TBM
The present loss involves two tunnel boring machines for railway tunnels known as EPB-TBM (Earth Pressure Balanced). The machines work in the opposite direction.
South Tunnel - Front 1: Performance problems occurred during the installation of the concrete rings for the tunnel lining, as well as subsidence along the drilling trajectory at different locations and on different dates. The first subsidence was not significant and the second was small, but a considerable settlement occurred at the location of the last three rings. This caused the total blockage of the equipment and obliged the Insured to carry out a revision of the heads, with damage also noted to the rotating shafts that necessitated a complete repair.
North Line - Front 2: This machine started drilling after initiating the works in the South Tunnel. Its design was improved following the experience gained during the work in Front 1, increasing the efficiency in the handling of the material that was being drilled (boulder). As with the previous Front, the machine blocked before reaching the maintenance area programmed for the shield, with similar damages to the rotating parts.