Análise numérica do efeito de grupo na capacidade de carga em fundações estaqueadas

Abstract

Industrial reservoirs are large containers intended for the storage of fluids at atmospheric pressure and at pressures above atmospheric. These tanks can store a wide variety of products involved in production in an industrial unit. An important analysis is the support structure for these reservoirs, for example the foundation and its interaction with the soil. Deep foundations in piles are traditionally used as a foundation engineering solution for constructions of this type of design in the city of Uberlândia (MG). In some cases, depending on the dimension of the load coming from the columns, it is common to use composite pile groups with two or more. The load capacity of these groups of foundations is not provided by the algebraic sum of the strength of the piles that compose it, as there is the action of the group effect on them. The purpose of this work is to evaluate the best solutions for the foundation for an industrial reservoir, considering the effect of the interaction between the piles (group effect) on the load capacity of pile foundations composed of 4 and 16 piles. The analyzes were made from comparisons between the methods proposed in the literature and the finite element method, using the “equivalent pier” artifice proposed by Poulos and Davis. Some methods underestimate the real load capacity of the plie groups, as observed for the group consisting of 4 piles, where the efficiency of the pile group is 66%, that is, 34% of the group strength is dissipated due to the interaction between the piles, stresses bulbs of intersecting, for the group with 16 piles, the efficiency of the group is 52%, therefore, it was found that the larger the group, the greater the loss of strength due to the group effect. Solutions with spacing between piles greater than conventional ones must be analyzed to find out better ways to reduce this effect. As a consequence of the group effect, analyzed by the proposed methods, the pile groups present settlement below those allowable, where the maximum settlement that the groups can suffer is 40 mm or 10% of the diameter of the piles, and for the pile group consisting of 4 piles, the maximum displacement that the pile group suffers is of 3.76 mm, less than 1% of the diameter, and for the pile groups of 16 a settlement of 6.71 mm, less than 2% of the diameter. Therefore, due to the low settlement results of pile group, the foundation structure of both groups is underused.