Methodological contribution to predict the preliminary bearing capacity of root piles embedded in soft rocks located in Northeastern Brazil

The bearing capacity of a pile installed in a rock is usually predicted through the recommenda-tions of technical standards, empirical correlations, theoretical analyses, and/or full-scale loading tests. These methods use strength and deformability parameters, as well as parameters of the structural elements in contact with the rock. In general, geotechnical investigations carried out on rocks are far more complex, requiring longer periods and at higher operational costs. In this sense, the concepts applied in Rock Mechanics, such as geomechanical classifications, can contribute to better predictions on the behavior of piles embedded in soft rocks. This research analyzed data from piles whose stratigraphic profile had sections embedded in soft rocks that had been submitted to static load tests. After soil characterization was performed, multiple methods available in literature to estimate the bearing capacity of rock piles were evaluated and a method to estimate the failure load of root piles with sections embedded in soft rock was proposed. The presented formulation agreed fairly well with experimental values and can be easily applied in daily practice, being especially appropriate for preliminary design and dimensioning of piles embedded in soft rocks.