The eruption of the La Palma volcano in 2021 marked a milestone in geology. This volcanic event, which left a devastating impact on the island, also gave rise to an emergency civil engineering project: the construction of a road that would traverse the lava flow and restore the vital north-south connection on the western slope of the island.

The magnitude of this undertaking became evident when considering the challenges detailed by Pilar Segura Pérez, Head of Materials and Laboratory Service, and Antonio José Nievas Guadix, Project Manager, from the company DRAGADOS. These challenges ranged from extreme conditions in the environment to innovative solutions in terms of materials and technology.

A primary challenge was the ground temperature, reaching 300 to 400 degrees Celsius. To monitor this variable that posed risks to people and materials, temperature probes were installed, which continue to be used today to monitor a lava flow that will take approximately 20 years to cool completely. Additionally, thermographies were conducted using drone flights to define the optimal road layout, minimizing contact with the extremely hot ground.

Another notable obstacle, as reported by the speakers, was the difficulty of conducting surveys in a highly irregular and dangerous terrain. Moreover, the presence of volcanic gases posed potential health risks for the workers. Advanced technologies such as ground-penetrating radar, capable of detecting lava tubes and buried structures up to 10 meters deep, were employed to address these challenges.

The strategic location of the road layout was crucial to ensuring the safety of the project. It was kept away from both the volcanic cone, due to its high temperature, and the sea, to avoid exposure to toxic gases.

Before construction, a meticulous 3D modeling of the layout was carried out using state-of-the-art tools. Additionally, stone materials from the eruption itself were used, requiring the implementation of mobile basalt crushing machines. For the preparation of artificial granular material, asphalt and concrete plants were installed, as they were not present on the island after the eruption, along with three crushing plants.

The triple insularity of the area (Canary Islands, La Palma island, and the area isolated by lava) added complexity to the project, as the lack of access to basic resources such as water and electricity required special logistical and energy solutions.

A noteworthy aspect of this project was its completion in May 2023, in less than a year from its initiation, showcasing the efficiency and commitment of the involved teams.

The road, connecting 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 as existing roads were partially buried by the volcanic flow.

In scientific terms, one of the most notable milestones of this construction was the execution of asphalt mixtures in a hot lava flow zone. This was the first time worldwide, as highlighted by the speakers, and represents a significant achievement in the field of road engineering.

Working conditions during construction were undoubtedly challenging. Workers had to face health risks due to exposure to volcanic gases and particles, requiring the use of masks and appropriate protective equipment.

In addition to technical challenges, the project also addressed social and environmental aspects. Sustainable solutions were sought, both in terms of materials and construction practices, to minimize environmental impact and respect the natural beauty of La Palma.

In summary, the construction of the road on the La Palma volcano is a testament to human ability to face extreme challenges with ingenuity and determination. This project not only restored an essential connection on the island but also made a mark in engineering by pushing boundaries in construction in hostile volcanic environments.

References:

- La Vanguardia: https://www.lavanguardia.com/vida/20230525/8993682/abierta-carretera-discurre-sobre-coladas-erupcion-volcan-palma.html
- La Razón: https://www.larazon.es/economia/carretera-palma-laderas-lava-gran-desafio-acs_2023071664b361b91f1191000171fa21.html

Road Construction on the Volcano: https://www.youtube.com/watch?v=SG_88II9n_I

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