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The need for understanding the interaction between the elements of a piled-raft foundation system becomes relevant when one of the piles collapses, presents a defect related to the installation procedure, or when it is sought to optimise the number of piles to meet the criteria of load capacity and admissible settlement. In the paper, 20 small-scale 1g load tests were performed in model piled-raft foundations placed within a cylindrical container. Pluviated sand under vertical loading was adopted to evaluate the cross-correlated qualitative behaviour of piled rafts with and without the presence of a single defective pile in systems of four, nine and 16 piles. The defects were simulated by the variation of the length of the pile, considering it shorter or absent, at distinct positions on the system – that is, corner, edge and centre of the raft locations. The results indicate that the position of the defective pile may be more detrimental to the foundation stiffness and load capacity than the level of damage of the pile, such as the cases evolving the presence of defective piles in the corner position.

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O trabalho analisa a evolução de recalques do edifício Hyde Park Cavalry Barracks, em Londres, partindo de simulações numéricas axissimétricas em elementos finitos. A edificação apresenta uma fundação do tipo radier estaqueado, construído sobre uma espessa camada de argila, representada pelo modelo constitutivo Cam-Clay modificado. Dados da obra e parâmetros do solo foram obtidos através dos trabalhos de Hooper (1973) e Gasparre (2005). A sequência de etapas construtivas da fundação foi considerada e os recalques previstos foram comparados com dados de monitoramento e com as previsões numéricas de Hooper (1973), Hain e Lee (1978), Sales et al. (2010) e Bernardes et al. (2019). A análise proposta difere daquelas publicadas anteriormente por não utilizar parâmetros do solo retroanalisados dos dados de monitoramento de recalques da edificação. Os resultados indicam razoável concordância entre os valores previstos e medidos, ressaltando a escolha adequada do modelo constitutivo Cam-Clay modificado e a importância da definição da inclinação da reta de recompressão na análise de argilas muito sobreadensadas.

This study presents the evaluation of the performance of grain silos reinforced by rigid inclusions in soils of the Central-West region of Brazil, during its construction and operation. Therefore, a group of eight silos with 32.4 m in diameter, 30 m in height, and 12,000 t of storage capacity (each silo) was numerically analyzed using the three-dimensional Finite Element Method (FEM, Plaxis 3D). The stratigraphy of the Experimental Field of the University of Brasilia, Brazil (CEGUnB) was considered in the analysis. The performance of using a system of rigid inclusions to reinforce the soil beneath the raft was compared with the behavior of an isolated raft. Two models were developed: in the first one, an independent silo was considered, its behavior was analyzed during its construction and operation stages by varying the length of the inclusions; in the second model, the group of eight silos was considered and their behavior was studied for different combinations of loading. The rigid inclusions system proved to be an efficient foundation solution that allows controlling total and differential displacements during the construction and serviceability stages of the silo, helping to prevent the formation of cracks in the structural elements and grain contamination by the excessive opening of the raft-perimeter beam structural joint.