Use of Passive Berms in Basement Construction
摘要
Excavation for a deep basement has become one of the most challenging tasks in urban construction. The majority of these developments face a problem of restricted setback with property boundary surrounded by other existing structures. This situation draws geotechnical engineers’ attention in providing a stable retention system. Such circumstances end up limiting the use of lateral support in terms of ground anchors for the retaining system, as they encroach into other properties. Further, adopting other construction methodologies like top-down construction with internal steel struts would be an effective solution but operationally challenging and economically not attractive. In such conditions, and to facilitate stable excavation, an alternative excavation method by introducing a temporary passive berm inside the excavation pit can be an ideal choice. Temporary passive berms provide an effective means of enhancing the short-term stability of embedded retaining wall. Implementing such practices proved to be cost-effective and provide a stable retention system, until the permanent connection beams or slabs are in place. This paper covers the analysis and design of two retention systems supported by passive berms in challenging environment and ground conditions. This paper also illustrates the performance of the installed retention systems with the predicted and monitored wall deflections of one of the projects.