Analytical Method for Prediction of Progressive Deformation Mechanism of Existing Piles Due to Excavation Beneath a Pile-Supported Building

After excavation beneath existing basement of a pile-supported building, prediction of the pile response is an interesting topic in geotechnical engineering. This paper presents a new load transfer function to capture the relationship between unit skin friction and shaft displacement. As to the load transfer function of an individual pile in pile groups before and after excavation, load transfer functions of skin friction and end resistance are proposed considering interactive effects among piles. To get a quick estimation on the pile response before and after excavation, a new highly effective iterative computer program is proposed using the proposed load transfer functions. Comparisons of the measured results, the present computed results and the calculated values derived from other approaches are made to check the reliability of the proposed method. Furthermore, a parameter study is carried out to evaluate the ultimate value of skin friction and end resistance of the pile subjected to stress relief due to excavation, and the influence of the parameters related to the proposed load transfer models on the pile response is also evaluated.