Analysis of the behavior of piled foundations in unconventional soil

Abstract

Building foundations using pile groups generally assume that the piles absorb the entire load of the structure. However, it is known that pile caps rest not only on the piles but also on the surrounding soil. These foundations involve great complexity in the phenomenon of load sharing, especially when they are situated on unconventional soils, such as tropical climate soils. To study this behavior, static load tests were conducted on real foundations. These tests were also used to calibrate a three-dimensional finite element numerical model (FEA-3D) using Rocscience's RS3 software. The results showed that the settlement corresponding to the allowable load of the pile groups was significantly lower, ranging from 22 % to 73 %, compared to pile caps that exert contact pressure on the soil. For pile groups, the efficiency ranged between 92 % and 109 %, while for pile caps with contact, it ranged from 132 % to 178 %. In this sense, it becomes evident that estimating the settlement of the pile group based on the conventional design, which does not consider the contact between the cap and the soil, can significantly underestimate the settlement, and provide an overly optimistic analysis of the soil-structure interaction.