Shape of ground surface settlement profiles caused by excavation

There are two general types of settlement profiles induced by excavation, the spandrel type and the concave type. Based on a regression analysis of the field observations of settlement curves with predominantly cohesive subsurface conditions, an empirical method for predicting the spandrel and concave settlement profiles is proposed. The proposed method is verified through several case histories. For comparison, the results obtained from other empirical methods are also presented. The proposed method provides a fairly good prediction of ground surface settlement and yields better prediction of angular distortion than other empirical methods for the concave- and spandrel-type settlement profiles. Furthermore, the relationship of cantilever area and deep inward area of wall deflection is established which can be used as the first approximation to predict the type of settlement profile.