Surface Settlement Adjacent to Braced Open Cuts

A semigraphical procedure is developed to predict the settlement gradient of the surface adjacent to a braced open cut. A review of existing methods for defining the zone of influence for underpinning discloses that present methods are not verified by field observations. The theoretical background used in developing the solution is presented. The soil mass behind the bulkhead is treated as a semi-elastic quarter-section that is stretched when the bulkhead moves towards the open cut. A typical example based on an observed open cut in Chicago clay show good correlation between the predicted and the measured settlements.