Effect of Corners in Strutted Excavations: Field Monitoring and Case Histories

Abstract

This paper discusses the effects of corners on wall deflection and ground movement around multistrutted deep excavations. To assess the significance of such effects in a typical-sized excavation in Singapore, a field monitoring exercise was conducted into an excavation in soft marine clay. Field data from this exercise indicate that the strengthening effect of the corner can lead to a significant reduction in wall deflection and ground settlement. Finite-element back-analyses of the excavation also showed that, where corner effects are significant, three-dimensional analysis may be able to offer significantly better predictions of movement than two-dimensional analysis. Comparison with several other excavation projects where corner effects were considered or observed suggests that the significance, or otherwise, of such effects depends on three factors: the length-to-depth ratio of the excavation, the depth to a relatively stiff stratum, and the stiffness of the strutting system.