Limitations Of Predicting Deformations During Excavation In Soft Clay ? Summary

Detailed measurements made at a test section adjacent to a deep braced cut and other published data are combined to illustrate the limitations of the common methods of predicting movements associated with excavations in soft to medium clay. While past performance data can be used to estimate expected responses before construction in many cases, actual wall and soil deformations throughout construction can only be estimated using finite element procedures. Success of such analyses depends equally upon considering all aspects of construction that induce strains in adjacent soil, such as wall installation, excavation and bracing sequence, and time, and adequately modeling soil stress-strain behavior. Even when these two criteria are met, soil deformations can not be predicted adequately when strain levels exceed those that produce peak shear stress.