Comparing Theoretical Predictions and Guidelines Against Pile Test Data for CFA Piles in Glauconitic Sands in Belgium

Estimating the axial bearing capacity and load-settlement response of pile foundations in glauconitic sands by means of engineering practice tools can encounter limitations. Glauconite is an iron potassium phyllosilicate mineral with a characteristic green colour, which forms dark green rounded aggregations, which often resemble sand grains. In geotechnical context, glauconitic sand presents challenges due to its tendency to transform from coarse-grained material into fine-grained material through particle crushing, and can impact pile foundation installation and performance. Such complexities can make accurate pile settlement prediction and design challenging. This study assesses the predictive power of past and current guidelines in Belgian practice, as well as a t-z approach, to predict the load-settlement response of piles in glauconitic sands. For this purpose, the theoretical predictions are further compared against data from CFA pile tests conducted in Belgium. A systematic parametric analysis investigates how the selection of model parameters impacts the pile load-displacement response. The findings emphasize the need for careful parameter selection to accurately represent the properties of glauconitic sands and achieve reliable outcomes.