Analysis of a database of instrumented static load tests on continuous flight auger piles in tropical soils

Abstract

This article assesses the behavior of full-scale static load tests (SLTs) conducted with instrumentation for strain measurements, in order to provide insights into the pile load transfer curves along its length. A collection of instrumented SLTs from a specific region offers a valuable dataset for the geotechnical community, which can be leveraged for machine learning-based neural network studies and probabilistic-statistical analysis, ultimately enhancing the reliability of regional semi-empirical methods. This study presents an analysis of a database containing the results of 80 instrumented SLTs conducted on CFA (continuous flight auger) piles in the metropolitan area of Goiânia, Goiás, Brazil, spanning from 2016 to 2022. It establishes correlations between the pile’s maximum skin friction (ql max) and soil resistance, as well as between the pile shaft and pile base resistances, and relative displacement at the pile-soil interface (δint). The geotechnical surveys accompanying each SLT are also included in the database under examination, aiding in the definition of a representative geotechnical profile of Goiânia’s soil. The ql max values derived from the database exhibit significant dispersion compared to the semi-empirical methods commonly employed in Brazil. Additionally, these values span a broad range of δint, with considerably lower values for the superficial, porous, and structured layer of sandy clay compared to the deeper layers.