Effets des anomalies géométriques et matérielles sur le comportement statique des pieux coulés en place

Details

Supervisors

Sgambi, Luca

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil des constructions

Abstract

enThe performance tests being less cost efficient than the integrity test, it becomes financially interesting to evaluate the performance of a defective pile knowing its geometry and the position of the anomalies that may occur. The goal of this thesis is to analyze the impact of the geometrical and material anomalies on the performance of the pile. To help us achieve our goal, we have first defined the anomaly then the different existing types, how they form and the different integrity test to figure out their position. H.G. Poulos had already study the behavior of defective piles in 1995 without explaining his method in detail. Our will was to reproduce his model developing an approach representing the pile using a series of springs. Going further into our reflection we decided to analyze the shape, position, footprint of the anomaly and the chance of a supplementary base emerging into the anomaly. To get as close to the real behavior of the pile, we created a Plaxis 2D model based on assumptions made by K. Petek, C.W. Felice et R.D. Holtz in 2002. Three cases have been studied : the soil and concrete having a linear elastic behavior; the soil having a Mohr-Coulomb behavior and the concrete having a linear elastic behavior; the soil and the concrete having a Mohr-Coulomb behavior. The results obtained for the first case in FEM correlated with the approach representing the pile using a series of springs. For the two other cases, the conclusions are the same as the first case but the results’ look are different. A necking of the shaft will lower the rigidity of the head of the pile whereas a bulge increase the rigidity. The highest the anomaly forms on the pile the more it will lower the rigidity of the pile. If the anomaly has a bigger footprint, the rigidity will increase in case of a bulge whereas it will decrease in case of a necking. An anomaly of a rectangular shape has the biggest effect on the pile behavior and the triangular shaped anomaly affects the pile behavior the less. The elliptical shaped anomaly lays in between in term of effect caused to the pile.