Hybrid Method for Predicting the Response of a Pile-Raft Foundation to Adjacent Braced Excavation

Abstract

With the increasing development of underground spaces in cities, a critical indicator for the design of excavation in urban areas is controlling the damage potential of adjacent buildings. Unfortunately, the design of excavations in built-up areas is very challenging because no analysis method has been developed for predicting the influence of excavation on adjacent pile-supported buildings. In this study, the small-strain-based empirical method was adopted for calculating the free-field soil movement induced by braced excavation, and a two-step method was developed to calculate the pile-raft response to braced excavation based on solutions for layered materials. Both the vertical and horizontal responses of the pile-raft foundation are considered. The proposed method was validated through a comparison of its results with those from model tests, the finite-element method, and existing methods in the literature. The proposed method could provide acceptable results of the horizontal and double-directional response of a pile-raft foundation induced by excavation in homogeneous and layered soil. Therefore, it can be used for estimating potential damage from excavation to adjacent buildings.