Effect of diaphragm wall construction process on the performance of braced excavation

The construction of diaphragm wall panels inevitably changes the initial stress condition and causes movements in the surrounding soil mass, which will also affect the subsequent excavation performance. Majority of current design and analysis of deep excavations assume that the diaphragm wall is ‘wished-in-place’, largely because of the complexities involved to consider detailed wall installation process. Limited analyses suggested that neglecting the wall installation effect would underestimate the ground movement, structure deformation, and strut load during the major excavation stages. This paper develops realistic modelling procedure to simulate the complete construction process of diaphragm wall panels and subsequent excavation, and compares with the analysis assuming the wall ‘wished-in- place’. The ‘wall-installation-modeled’ approach can improve the accuracy of prediction and reduce discrepancy in the back analysis of deep excavations.