An Empirical Method for Analysis of Load Transfer and Settlement of Single Piles

An empirical method is developed for estimating the load transfer and deformation of drilled, in situ formed piles subjected to axial loading. Firstly, governing equations for soil–pile interaction are developed theoretically, taking into account spatial variations in: (a) shaft resistance distribution and (b) ratio of load sharing between the shaft and base. Then generic load transfer models are formulated based on examination of data from 10 instrumented test piles found in the literature. The governing equations and load transfer models are then combined and appropriate boundary conditions defined. Using an incremental-iterative algorithm whereby all the boundary conditions are satisfied simultaneously, a numerical scheme for solving the combined set of equations is developed. The algorithm is then developed into an interactive computer program, which can be used to predict the load-settlement and axial force distribution in piles. To demonstrate its validity, the program is used to analyse four published case records of test piles, which other researchers had analysed using the following three computationally demanding tools: (a) load transfer (t–z), (b) finite difference and (c) finite element methods. It is shown that the proposed method which is much less resource-intensive, predicts both the load-settlement variation and axial force distribution more accurately than methods: (a–c) above.