Three-Dimensional Numerical Parametric Investigation of the Influence of Large-Scale Overexcavation on Deep Excavations

Using a numerical analysis program based on the finite difference method (FDM), a study is conducted to reveal the mechanical behaviors of deep excavations influenced by a large-scale overexcavation, retained by a tieback pile wall. Based on an overexcavated deep excavation, the parameters used in the numerical models are verified using field observation. A parametric investigation is performed in order to analyze the influence of three factors, length of the wall, distance between the edge of overexcavation and the pile wall, and ovexcavation depth. According to the simulation results, the pile wall bottom is significantly influenced by the overexcavation and a deep overexcavation can cause the excavation collapse and retaining structure failure. Special emphasis is given to the analysis of horizontal pile wall deformation, ground settlement and potential slip surface. Conclusions obtained from the numerical study can provide guidelines on good practice in construction of anchored pile wall retained excavation in sandy soil.