The Vilavella tunnel comes with two tunnels with a length of 902 m and 869 m. Both tunnels have a single lane road, with a truncated circular section of 52 m² interior section.
The differentiated lithotypes throughout the tunnels correspond both to granite as well as partially metamorphosed sedimentary units via intrusion of the granite. In respect of plutonic materials, the only effective material corresponds to what is known as A Gudiña granite.
For harder rocks, perforation and blasting methods were used, and for the softer lithotypes, a backhoe with hydraulic hammer was used, excavating in accordance with NATM, applying supports based on projected cement, pins, mesh and trusses.
Once the excavation and tunnels support were completed, a concrete coating framework with a minimum thickness of 30 cm was installed.