Interpretation of pile load test failure using FEM simulation

Abstract

This paper examines two cases of instrumented piles that did not performed as intended. The first case is an O-cell test of a 1500 mm large diameter bored pile. The pile could not be loaded by the O-cell to its required test load of 1.5 times working load of 18.5 MN. The upper part of the shaft resistance was not fully mobilized at the end of test. The second case is the simulation of a conventional top loaded 1200 mm bored pile installed by the slurry method that has a significant soft toe layer resulting in a plunging failure at 2.5 times its working load at 25 MN. Using the FEM model to simulate the pile response, brittle plunging failure can be illustrated that correspond to the measured pile response at the time of failure. Also the model can be extended to see how the pile would have performed if there were no soft toe at the base of the pile. © 2006 Taylor & Francis Group.