Abstract:
This article presents a case study with analysis of field and numerical tests of helical pile foundations used for the tensile loads of the Guyed Towers of a transmission line in northeastern Brazil. We know that a work on a transmission line involves many challenges, because geotechnical properties can change during the execution of foundations. The helical piles showed geotechnical rupture after 5 years of installation, with a fall in structure and causing the transmission line to be shut down. All site data, soil Nspt tests, laboratory soil tests (characterization, densification, triaxial) were analyzed, verifying the variations along the foundations. Additionally, field trials were carried out in true magnitude in the foundations for rupture analysis. Subsequently, a numerical analysis was made as a comparison and analyses of the predicted and found results. Studies and probable cause, as well as the foundation reinforcement solution for each site, will be presented. Tests will also be presented prior to the installation of foundation reinforcements, to identify the last limit capacity of the soil, predicting periods of the year in which saturation may occur due to heavy rains.