Integrating finite element and load-transfer analyses in modelling the effects of dewatering on pile settlement behaviour

Abstract

A method of analysis is developed by integrating finite element (FE) and load-transfer analyses to predict the negative shaft resistance and settlement of piles due to ground water lowering. A program is written in MATLAB for linking the FE results of ground movements with the input interface system of a new pile load–settlement analysis program (named “PILESET”) developed by the author. PILESET is specially designed to allow automatic input of electronic site investigation data, although manual input of laboratory soil test data is also possible. Using PILESET, custom-defined load-transfer relationships can be either input manually or calculated internally by PILESET based on the input data from in situ or laboratory soil tests. To demonstrate the validity of the suggested analysis procedure, a case record is analyzed where sump pumping was to be carried out underneath a deep basement situated close to an existing building supported on 15 m long piles. Based on assumed steady-state flow conditions, ground settlements are calculated using FE analysis and used with site investigation data to predict the negative shaft resistance and settlement induced in the piles. The results are found to agree well with field measurements.