Influência do comprimento de estacas instrumentadas nocomportamento de sapatas de fundação

Abstract

In the context of small-scale construction projects in the Triângulo Mineiro region, the occurrence of foundation-related pathologies has become increasingly common. This is primarily due to insufficient knowledge of the geotechnical characteristics of the soil, which often leads to design errors in foundation sizing. Brazilian soils exhibit characteristics typical of tropical weathering processes, which underscores the need for more in-depth studies of their properties and of the soil–foundation interaction, particularly when considering the behavior of unsaturated soils. Studies conducted in the Uberlândia/MG region indicate that the local soils are lateritic in nature and exhibit collapse susceptibility. The objective of this research is to evaluate the variation in stiffness of Isolated Piled Raft Foundations (REI) by varying pile lengths of 4 m, 5 m, and 6 m. In addition, the study investigates load sharing and load distribution between the raft and piles for different pile lengths, compiling data obtained from previous research carried out at the Experimental Geotechnical and Foundation Research Site of the Federal University of Uberlândia. For comparative analyses of the isolated piled rafts, an experimental test of a piled raft with 6 m-long piles was performed using a slow maintained static load test under both in situ and inundated soil conditions. Numerical modeling using the Finite Element Method (FEM) was also conducted to simulate and compare the experimental behavior with the numerical model, aiming to deepen the understanding of the analyzed scenarios and enable extrapolation to other types of structures. The experimental tests demonstrated an increase in load-bearing capacity with greater pile lengths, showing a 30.72% increase between the 4 m and 5 m piled rafts, and a further 35.48% increase between the 5 m and 6 m foundations. The increase in bearing capacity was also accompanied by an increase in settlements. Furthermore, the load-sharing ratio between the raft and the piles ranged from 30% to 59% for the raft and from 41% to 70% for the piles, with the 6 m piles carrying the highest proportion of the applied loads compared to the 4 m and 5 m piles. Numerical analyses also highlighted their potential to provide more refined insights into the performance of piled raft foundations.