The influence of trenching diaphragm wall panels on deflection and bending moment of existing piles within piled foundation

Abstract

Conducting deep excavations for underground construction inside the cities requires diaphragm wall due to space limitation. The ground surface is affected by the trenching process. The construction of the diaphragm walls near deep foundations may not be avoided specially in the crowded cities. This research focuses on the deflection and bending moment of piled foundations near slurry trench. Since the trench is considered as a three-dimensional problem, a three-dimensional numerical analysis was used in this research. It was conducted using a commercial analysis software known as FLAC 3D. The numerical analysis method was verified using two case histories, one in Hong Kong and another one in Giza, Egypt. The results from the numerical analysis were in quite a good contrast with the field data results. This indicates that the trenching process could be numerically modeled with the proposed method and provides good results. The verified numerical analysis method was used to conduct a numerical parametric sric study that discusses the effect of multiple panels on adjacent connected pile groups or piled raft foundation. The parametric study showed that the pile deflection and bending moment are affected by the panel construction stages, pile location within the foundation. The pile deflection and bending moment are affected by the stages of construction. The piles near the trench are affected by the trenching process, while the piles far from the trench are affected by the dragging force of the pile near the trench.