Effect of deep excavation on an adjacent pile foundation

Abstract

The thesis studies the behavior of single axially loaded pile located close to a 30m deep braced excavation in Marine Clay corresponding to site conditions of the Kallang formation in Singapore. Parametric analyses were carried out, using non linear three-dimensional finite element methods (with Plaxis Foundation 3-D), comparing different pile lengths (17m, 30m and 42m) cross sections (solid concrete sections of 0.4m and 1.Om diameter) and proximity to the excavation (2m-10m). The results focus on the development of horizontal deformations and bending moments due to the excavation process. The computed results for end-bearing piles (42m long) are compared with semi-empirical design methods proposed by Poulos and Chen (1997). In general, this design method substantially underestimates the computed wall deflections and bending moments. This result confirms the importance of site-specific analyses for these types of complex soil-structure interactions.