3D stability analysis of gravity dams on sloped rock foundations using the limit equilibrium method

摘要

A convenient approach to performing stability analysis of concrete gravity dams is the so-called two dimensional‘‘gravity method.’’ However, concrete gravity dams located in valleys with sloped rock foundationabutments behave as three-dimensional (3D) structures and are often able to share compressiveand shear loads between adjacent monoliths, especially when shear keys are present. A general 3D limitequilibrium method was developed in this study to compute global sliding safety factors (SSFg) by consideringsequential load redistribution among adjacent monoliths when individual monoliths have mobilizedtheir sliding strength. Two validation examples of the sliding safety assessment of existing dams arepresented to illustrate the accuracy and efficiency of the proposed approach compared to that of the full3D numerical analyses conducted using the distinct element method. It is shown that gravity dams maybe formed by individual monoliths on sloped rock foundations that will slide if considered as isolatedstructures but will constitute a stable assembly when the load-sharing capabilities of monoliths are recognizedin the analysis.