Uso de modelo teórico para estimativa de parâmetros de resistência de solos reforçados com fibras de polipropileno

Abstract

Several studies have addressed using soil mixtures with polypropylene fibers in recent years. Including fibers in the soil improves its geotechnical properties, especially its shear strength. The improvement in resistance parameters can be assessed through direct shear and triaxial tests. Recently, theoretical models have been developed to predict the strength envelope of soilfiber mixtures without the need to perform strength tests on the composite. This work aims to verify the application of a theoretical model to predict the strength parameters of composites mixed with polypropylene fibers by comparing the results provided by the models with the results of strength tests obtained on soil-fiber mixtures with different fiber contents. The results indicated that the theoretical model showed significant differences from the experimental data, with an average percentage error of 41% for cohesion and 30% for friction angle. There was a tendency for the model to overestimate the friction angle. In the case of cohesion, the model tended to underestimate the values for normal stresses below 100 kPa and to overestimate cohesion for stresses above 100 kPa. The model's accuracy was better for estimating cohesion for lower ratios between length (L) and fiber diameter (D), and its application is recommended only for these conditions. As for the friction angle, verifying a trend with the L/D ratio wasn’t possible. Finally, the model estimated increasing values for the strength parameters as the fiber content increased. The experimental results did not always confirm this behavior, suggesting there is an optimum fiber content.