Three years, seven months and one day have passed since a backhoe, a loader and a truck began the clearing work to undertake the most expensive public work in Spain: a 5.1-kilometre double tunnel under the Teno massif, in the northwest of Tenerife.
At 10 a.m. on November 25, 2019, authorities and journalists shared the historic moment in the municipality of Santiago del Teide: the machines began to break stone in the Las Manchas area. Decades of intense debates and bureaucratic difficulties that delayed the start of work were left behind, including the threat of loss of the environmental impact statement and an appeal filed before the Administrative Court of Public Contracts, which delayed the starting gun for six months.
Thus began an unprecedented work in the Canary Islands that has represented a challenge for modern engineering and that has required special robotic drilling rigs equipped with water and percussion to combat the hardness of the basalt. “We do not know what we are going to find inside the massif,” José Luis Delgado, general director of Road Infrastructure, pointed out to this newspaper in the initial phase.
SYNCHRONIZATION
The complex procedure has included explosives connected to computers to activate the controlled detonations and a synchronized carousel between operators and machines, with trucks that removed the material demolished by the charges. So, 24 hours a day, seven days a week.
The magnitude of the underground work, with sections of almost 400 meters deep, has made it necessary to keep the technicians georeferenced at all times. The precision has been maximum, because any error, no matter how small, could cause a deviation and prevent the north and south tunnel mouths from meeting. In the section started in El Tanque, the operators found less consistent rock in the first year, which made it necessary to reinforce the supports, slowing down the progress of drilling.
FINAL STRETCH
Last Monday, the north and south of the island shook hands under the Teno massif, a gesture symbolized by two workers on both sides of the mountain range. Heavy machinery drilled the last two meters that separated each of the two galleries drilled from Santiago del Teide and El Tanque, thus completing the union of both sections after digging 4,855 meters.
The twin tunnel, which runs in parallel, has already drilled 4,555 meters, which is equivalent to 97% of the underground passage, which will be completed in August, according to the forecast of the Ministry of Public Works, Transport and Housing. In just over three and a half years, almost 9.5 kilometers have been drilled underground.
The works will be completed with two false tunnels (140 meters in the south mouth and 100 meters in the north mouth), which will increase the length of the longest tunnel in the Canary Islands -and one of the longest in Spain- to 5.1 kilometers foreseen in the project.
The largest road engineering work carried out in the Archipelago, with a budget of 256 million euros, will mark a before and after in island mobility and will put an end to the collapse of traffic on the TF-5 motorway, in addition to facilitating the economic dynamism between the north and south of the island of Tenerife.
More than 17,000 vehicles are expected to use the dual carriageway daily to cross the Teno massif, an amount that far exceeds the initial forecast of 5,000 cars. Technical studies indicate that within a decade traffic will be more than 30,000 vehicles.
