Analysis of geotechnical parameters variation on a numerical modelling of aerogenerators foundations on sandy soils

Abstract

One of the challenges in geotechnics, considering Brazil, is related to investigations geotechnical. To understand the stress x displacement behavior of the soil below the foundation, it is necessary to predict the soil parameters, such as modulus of elasticity, coefficient of Poisson, friction angle, cohesion, specific weight and dilatancy angle. However, the level of uncertainty in predicting soil parameters is significant. Therefore, the objective of this research is to evaluate predictions of behavior, in terms of resistance and displacements of a wind turbine foundation, presenting significant variations when parameters are estimated by different field tests. To achieve this goal, two approaches were developed, the first being a sensitivity analysis of the assay parameters Standard Penetration Test (SPT) carried out in a wind farm in the city of Trairi-Ceará and the second, an assessment of displacement predictions considering the use of information obtained from the Standard Penetration Test (SPT) and Ménard Pressuremeter tests Test (PMT), both carried out in a wind farm in the city of Taíba-Ceará. In both In these cases, the behavior of the shallow foundation of a wind turbine based on soil was analyzed sandy soil from numerical modeling. It was observed, for the circumstances evaluated, that deformability parameters (modulus of elasticity) significantly affected the displacements, as opposed to resistance parameters (friction angle). With the use of PMT test results, more representative predictions were obtained, considering the groups studied compared to SPT. The maximum displacement variation in the first stage of the study was in the order of 10mm and in the second stage of the study, in the order of 32mm. With based on the marked variation in predicted results, it is observed that the level of uncertainty involving field tests and corresponding correlations is high. Furthermore, it was observed that the use of numerical modeling is essential in behavior analysis foundations of wind turbines or other structures, however, the importance of use of parameters representative of the soils being evaluated.