Earth pressure of layered soil on retaining structures

Abstract

Earth pressure evaluation of retaining structure is not a new thing in geotechnical engineering. Up to date, many analytical and numerical approaches have been developed, but limitations of these available approaches are obvious for the application in some situations. The main objective of this paper is to develop a method to predict the earthquake pressure of retaining structures based on wedge method with as few limitations as possible. The developed method is suitable for retaining structures in the case of layered backfill with zero slope angle from horizontal level and with curved failure surface. To generate a curved failure surface, the sliding wedge is divided into many thin-layer micro-elements and the equilibrium equations of each micro-element are established. In the case of seismic analysis, the seismic actions are considered as static inertia forces on layered micro-elements. The shape of failure surface is determined by using available optimization method. Effects of the friction angle between wall and backfill soil on the distribution of earth pressure and the shape of failure surface were investigated, and earth pressures estimated based on curved and linear failure surfaces were compared. Analysis results indicate that the potential failure surface in the backfill soil depends on the friction angle between wall and backfill soil. For small friction angle, the failure surface tends to be planar. The active earth pressures corresponding to curved and planar failure surfaces are almost identical, but the discrepancies between the results of the two failure surface are large and increase with the increase of wall friction. Comparisons between results of the proposed method and those of the available methods as well as experimental results were conducted. Comparison result indicates that the merits of the proposed method are obvious.