The eruption of the La Palma volcano in 2021 marked a milestone in geology. This volcanic event, which left a devastating footprint on the island, also gave rise to a emergency civil engineering project: the construction of a road through the lava flow and re-establish the vital north-south connection on the western side of the island.
The magnitude of this undertaking became evident when considering the challenges which Pilar Segura Pérez, Head of the Materials and Laboratory Service, and Antonio José Nievas Guadix, Site Manager, of the company DRAGADOS, detailed in their presentation. These challenges ranged from extreme environmental conditions to innovative solutions in terms of materials and technology..
A primary challenge was the soil temperatureThe temperature reached 300 to 400 degrees Celsius. In order to monitor this variable, which put people and materials at risk, the following were installed temperature probesThe lava flows are still in use today to monitor a lava flow that will take approximately 20 years to cool down completely. In addition, the following were carried out thermography using drone flights to define the optimal road layout, thus minimising contact with the extremely hot ground.
Another major obstacle, according to the speakers, was the difficulty of drilling in highly irregular and dangerous terrain. In addition, the presence of volcanic gases posed potential risks to the workers' health. To address these challenges, advanced technologies were employed such as the georadarcapable of detecting lava tubes and houses buried up to 10 metres deep.
The strategic location The road layout was essential to ensure the safety of the construction site. It was kept away from both the volcanic cone, due to its high temperature, and the sea, in order to avoid exposure to toxic gases.
Prior to construction, a thorough 3D modelling of the layoutThe project was carried out using state-of-the-art tools. In addition, the following were used stone materials from the eruption itselfThis required the implementation of mobile basalt crushing machines. For the preparation of artificial Zahorra, agglomerate and concrete plants were installed, since they did not exist on the island after the eruption, together with three crushing plants.
The triple insularity of the area (Canary Islands, island of La Palma and lava-isolated area) added complexity to the workThe lack of access to basic resources such as water and electricity made it necessary to implement special logistical and energy solutions.
An outstanding aspect of this project was its completion in May 2023in less than a year since its inceptionThis is a testament to the efficiency and commitment of the teams involved.
The road, which connects roads LP-215 and LP-213, represents a high-performance infrastructure that restored a vital north-south connection on the island after an investment of 38 million euros. This was essential, given that the existing roads were partially buried by volcanic ash.
In scientific terms, one of the most notable milestones of this construction was the execution of the bituminous mixtures in a hot runner area. This was the first time this had been done at the global level, as the speakers highlighted, and represents a significant achievement in the field of road engineering.
The working conditions during construction were indeed nightmarish. Workers faced health risks due to exposure to volcanic gases and particles, which required the use of appropriate masks and protective equipment.
In addition to the technical challenges, the project also addressed the following issues social and environmental aspects. Sustainable solutions were soughtThe building is designed to minimise environmental impact and respect the natural beauty of La Palma, both in terms of materials and construction practices.
In short, the construction of the road over the volcano on La Palma is a testament to the human capacity to meet extreme challenges with ingenuity and determination. This project not only re-established an essential connection on the island, but also left a mark on engineering by opening new frontiers in construction in hostile volcanic environments.
Bibliography:
Construction of roads over the volcano: https://www.youtube.com/watch?v=SG_88II9n_I
