A novel approach to estimating the bearing capacity stability of geosynthetic reinforced retaining walls constructed on yielding foundations

Yielding foundation conditions have been shown to adversely affect the stability and behaviour of overlying geosynthetic reinforced soil walls. To avoid serious problems and maintain a cost-effective design, careful consideration must be given to short-term stability. Previous research has shown that lengthening and stiffening the bottom reinforcement layer of the wall can increase the external stability, but the magnitude of this increase is not well understood. To provide insight regarding the potential benefit of lengthening and stiffening the bottom reinforcement layer, a numerical investigation is made of the plastic collapse mechanism due to bearing capacity failure of the foundation deposit for the case of a 6 m high geosynthetic reinforced retaining wall on a 10 m thick soft to firm visco plastic clay stratum. The calculated behaviour of the wall is compared with that from typical and novel design considerations for both a conventional reinforced wall and a wall where the bottom reinforcement layer has been extended and stiffened. A parametric study of the extended bottom reinforcement layer stiffness and interaction is reported, and the influence on the external stability is discussed.Key words: reinforced soil wall, soft yielding foundation, bearing capacity design, numerical analysis.