Effect of Deep Supported Excavation on the Adjacent Deep Foundation

摘要

In dense urban environments where land is scarce and buildings are closely spaced, cut and cover excavations are widely used for basement construction and development of underground facilities. One of the main design constraints in these projects is to prevent or minimize damage to adjacent structures. In this study, a database for soil properties of Baghdad city zones has been obtained using (GIS-technique) which were then used in a 3-D finite element program PLAXIS 3D FOUNDATION to investigate the effect of a common cantilever supported excavation on the behavior of adjacent deep foundation. The supported material is modeled via a linear elastic model while the non-linear stress-strain behavior of cohesive and cohesionless soils is modeled using Mohr-Coulomb model. In the numerical study, a parametric study is carried out to address the influence of the supported excavation on the lateral displacement of adjacent pile with various diameter, length and distance from the excavation face. The results showed that the Mohr-Coloumb model parameters C_u and E are the most effective on the behavior of piles near supported excavation. And from the analysis, the maximum lateral deflection of pile depends on the pile-sheet pile wall distance and decreases significantly by increasing the distance. It has been decreases by approximately (76%) when the distance increased from 1 m to 9 m. Also both the diameter and length of the pile dose not play an important role for the lateral displacement when the distance is equal or greater than 0.8H (i.e. 5 m).