Abstract: Although the deep excavation support is a temporary project, the safety of the excavated area throughout the entire foundation excavation and construction is not only directly related to the excavation support itself, but also may result in the damage to adjacent buildings and/or utilities. Further, it might pose a threat to the loss of properties and even public and construction workers lives. Therefore, the importance of the deep excavation support design should be properly recognized by the designers as well as the owners. The shear strength is the most critical factor in the deep excavation support design. The three factors, such as, groundwater level, freezethaw effect and earth excavation sequence, that could impact the shear strength are evaluated in this paper based on a practical project. Typical issues that encountered in the foundation excavation and correspondent countermeasures are analyzed in the paper.

Key words: deep excavation support, shear strength, groundwater, freezethaw effect, earth excavation