A Parametric Numerical Study for Diagnosing the Failure of Large Diameter Bored Piles Using Supervised Machine Learning Approach

Abstract

The full-scale static pile loading test is without question the most reliable methodology for estimating the ultimate capacity of large diameter bored piles (LDBP). However, in most cases, the obtained load-settlement curves from LDBP loading tests tend to increase without reaching the failure point or an asymptote. Loading an LDBP until reaching apparent failure is seldom practical because of the significant amount of settlement usually required for the full shaft and base mobilizations. With that in mind, the supervised learning algorithm requires a huge labeled data set to train the machine properly, which makes it ideal for sensitivity analysis, forecasting, and predictions, among other unsupervised algorithms. However, providing such a huge dataset of LDBP loaded to failure tests might be very complicated. In this paper, a novel practice has been proposed to establish a labeled dataset needed to train supervised machine learning algorithms on accurately predicting the ultimate capacity of an LDBP. A comprehensive numerical parametric study was carried out to investigate the effect of both pile geometrical and soil geotechnical parameters on both the ultimate capacity and settlement of an LDBP. This study was based on field measurements of loaded to failure LDBP tests. Results of the 29 applied models were compared with the calibrated model results, and the variation in LDBP behavior due to change in any of the hyperparameters was discussed. Accordingly, three primary characteristics were identified to diagnose the failure of LDBPs. Those characteristics were utilized to establish a decision tree of a supervised machine learning algorithm that can be used to predict the ultimate capacity of an LDBP.

Modified Meyerhof approach for forecasting reliable ultimate capacity of the large diameter bored piles

“…First, an assessment study was performed to evaluate the reliability of the estimated LDBP ultimate capacity using the capacity-based method 31 and the different settlement-based methods 1 , 8 , 9 . This assessment study was based on the results of the parametric numerical models of the comprehensive study 6 that investigated the effect of different parameters on the ultimate capacity of LDBP. The parameters influencing the ultimate capacity and settlement of the LDBP were classified into two main categories.…”

“…In the third phase, the results of the parametric study 6 were utilized to investigate the relation between soil resistance and pile settlement at the three load transfer stages (Elastic, Mobilization, and Failure). The propagation of the plastic zones around the pile shaft and under its base have been monitored to differentiate between the elastic, mobilization, and failure stages.…”

“…Second, the established numerical studies to simulate the behavior of the Alzey case history’s LDBP 32 , 37 . Third, the comprehensive parametric study 6 that carried out to investigate the effect of different geometrical and geotechnical parameters on the ultimate capacity and settlement of the LDBP. The following sections give a brief about each of those three studies.…”

“…A comprehensive numerical parametric study 6 was carried out to investigate the effect of pile geometrical and soil geotechnical parameters on the ultimate capacity and settlement of LDBP. This study was based on the field measurements of the loaded to failure Alzey LDBP test.…”

“…In that way, it was possible to examine the specific effect of each factor.

Figure 4 Factors affecting large diameter bored pile behavior (After Al-Atroush et al 6 ).

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