Estimation of Ground Movement and Wall Deflection in Braced Excavation by Minimum Potential Energy Approach

Abstract

Prediction of soil displacements adjacent to braced excavations is critically important, especially in urban areas, to prevent any potential damage of adjacent buildings, service lines, and other infrastructure facilities. In the present study, a new theoretical approach was proposed for estimation of ground deformation and wall deflection at any section within the influence zone of braced excavation, considering soil deposit as a three-dimensional elastic continuum. The principle of minimum potential energy was applied to obtain the governing differential equation for both horizontal and vertical displacements in the continuum. A flowchart of design procedure was presented in which soil parameters λ and G (Lame’s constants) were incorporated to characterize soil deformation. For proper linkage between horizontal and vertical soil movements, soil displacement profiles at various locations around excavation were assumed. The computed results were compared with the observed values obtained from three different case studies in which excavations were performed mainly in soft to medium clays. The present study showed that the proposed method predicts well for different field conditions and can be used as a simplified approach to obtain ground and wall deformations at various depths and horizontal distances.