Use of Jet Grouting to Limit Diaphragm Wall Displacement of a Deep Excavation

Excessive lateral diaphragm wall displacement and the associated ground settlement are often the primary cause of damage of nearby buildings. It is therefore imperative to minimize diaphragm wall displacement during basement excavation if the integrity of adjacent buildings is of concern. This paper describes the application of a jet grouting scheme to reduce the diaphragm wall displacement of a six-level basement excavation. Based upon field experience of similar projects, buildings adjacent to the construction site may settle well beyond an acceptable limit if excavation is carried out without any protection measures being taken. In this excavation project, the soil mass within the excavation zone was partially jet grouted in an attempt to increase its passive resistance as an effective measure to limit wall displacement. Numerical analyses were carried out to assess the effects of jet grouting. Field measurements on wall displacement and ground settlement confirm the effectiveness of the improvement scheme.