OBJECTIVE:
Located near the town of Loncoche, in the Araucanía Region (Region IX), Chile, the substation sections the 220 kV Cautín – Ciruelos line and the 66 kV Temuco – Loncoche line, with the aim of improving the electrical infrastructure of the Araucanía Region.
AXIATECH was contracted by EDEMSA Chile, the company in charge of constructing the new Lastarria Substation, to carry out the engineering, supply, and construction of the foundations for the substation’s structures and equipment.
Given the technical challenges posed by the project’s typology and geographic location, it was necessary to conduct a state-of-the-art and best practice review of foundations. This resulted in the selection of helical piles as the most advantageous technical and economic option for constructing the project’s foundations.
CONVENTIONAL SOLUTION
In a geological context, the project area is located on fluviolacustrine deposits composed of sands and clays. Even during the summer season, the water table remains close to the surface, creating a complex and challenging geotechnical and soil mechanics scenario. The stratigraphic profile consists mainly of highly compressible, saturated soils with considerable organic matter content, necessitating the use of special, deep foundations to prevent future settlement and deformation problems.
In addition to the above, an important factor that directly affects foundation performance cannot be overlooked: the seismic complexity inherent in any construction project located in Chile. Indeed, the Lastarria substation is located just 88 km from the city of Valdivia, the site of the epicenter of the largest earthquake in recorded human history.
Therefore, it was mandatory to design deep foundations to meet the load requirements and seismic demands.
However, the geographical location and the nature of the soils created costly construction scenarios for carrying out the project. Additionally, the construction time exceeded the project’s expected timeframe for commissioning.
HELICAL PILE SOLUTION
Helical piles were an excellent alternative to overcome the challenges posed by the project and its conditions. However, as this was the first substation in Latin America to adopt new foundation techniques and alternatives, it was necessary to validate the selected foundation’s performance under various stresses through a high-level engineering process and subsequent field testing.
With the collaboration of a multidisciplinary team of engineers specializing in different areas, with extensive experience in the sector, and in conjunction with professionals from EDEMSA and TRANSELEC, we successfully overcame all the engineering challenges.
Additionally, thanks to thorough and well-supported engineering work, a field testing campaign successfully calibrated the mathematical models and hypotheses used in the design phases. This resulted in the acceptance, implementation, and homologation of the helical pile foundation alternative as the preferred foundation technique for power transmission and distribution projects in Chile.
RESULTS
During the construction phase, thanks to the implementation of installation, verification, and testing protocols, as well as state-of-the-art installation and measurement equipment, and the highly trained personnel involved in the construction process, the challenging milestones set during the planning phase were achieved throughout the project execution and control phases. Similarly, the rigorous quality control of the helical pile foundation system, for both the project supervisor and the owner, ensured the satisfactory completion of the project without any objections or nonconformities.
Similarly, thanks to the implementation of protocols and the expertise of the personnel assigned to the project by Axiatech, no accidents or claims related to occupational health and safety were recorded upon completion of the work.
Finally, compared to the conventional solutions initially considered, a significant reduction in construction time was achieved, along with a dramatic reduction in environmental impact, specifically in CO2 emissions. Thanks to all the advantages described, we can proudly affirm that the helical pile foundation solution provided by Axiatech is the best technical, economic, logistical, safe, and environmentally sound alternative for your project.
