A computational procedure to predict the load- settlement behavior of axially loaded piles in sandy soils

Abstract

In the early stages of design and analysis of structures that are supported by piled foundation, the stiffness of piles is often required to be evaluated. Without going through the complication of pile- soil system, piles can be simulated as springs if the load- settlement behavior of each pile is accurately determined. In this paper, the governing differential equation of pile displacement problem is implicitly solved through a sequence of computation steps. A simple Matlab M- file is built up to perform the computations and present the analysis results. The proposed computation scheme accounts for the nonlinearity of soil mechanical properties and for the non-homogeneity of the soil profile along the pile depth. Consequently, an iterative loop of recalculation and tolerance checking is used and convergence is achieved very rapidly. The procedure is then applied to calculate the pile- settlement behavior of an 1800 mm diameter and about 18m length concrete pile installed in dense to very dense sandy soil. The pile which has a working load of about 6670 kN, is one of the New Hindiya railway bridge piles located in the central part of Iraq. The pile was in situ tested under an axial load of about twice the working load. The results obtained by the proposed computation method compared well (the deviation is less than 10%) with the test results in terms of pile load settlement behavior. This may enhance the reliability of the proposed method.