Optimum Base Width of Gravity Retaining Walls of Narrow Backfilled with Recycled Materials

Abstract

The optimum dimensions of narrow backfill width gravity retaining walls backfilled with recycled materials are obtained by considering the four modes of failure, viz overturning of the wall about its toe, sliding of the wall on its base, eccentricity of the resultant force and bearing capacity failure below the base slab. An analytical method is presented to obtain a solution for the active earth pressure exerted by the backfilling of recycled materials like bottom fly ash, course coal refuses, foundry sand, foundry slag, mill tailing, scrap tires, reclaimed asphalt pavement (RAP) and recycled concrete aggregate (RCA). The proposed method uses the limit equilibrium method with planar slip surfaces. Three different failure mechanisms of the active wedge are considered, namely mechanism 1 (active wedge formed by a single block), mechanism 2 (active wedge is composed of two rigid blocks, one slipping with respect to the other) and mechanism 3 (which considers three blocks). Using these three mechanisms, the magnitude of active earth pressure acting on the gravity wall and point of application of active thrust from the bottom of the wall are computed. The influence of various parameters on the optimum dimensions of the gravity retaining wall is presented in the form of design charts.