ABSTRACT
Stability is a crucial consideration in the design of embedded cantilever walls. There are many methods available for this design. However, the choice for a suitable method is not easy as the meaning of stability differs significantly between methods. Communication of the calculated wall stability could pose false security between designers, asset owners and operators. Designers often regard active earth pressures as loads and passive earth pressures as resistances, but is this correct? Following a rational examination a postulation is made on the nature of earth pressures on embedded structures. This leads to the formulation of a new model based on limit equilibrium to calculate wall stability. The formulation overcomes the issues with the existing methods and is shown to be consistent for soil spectrum maintaining a constant margin for a given stability design. The proposed method relates the Factor of Safety as a function of the restoring moment capacity at critical equilibrium and What You Design Is What You Get (WYDIWYG). For example if the required factor of safety is two then the design ensures the restoring capacity of the wall is two times that at critical equilibrium. It provides a new platform for objective assessment of wall stability. The approach is reliable, economical and suitable for conforming design to Australian Standard AS 5100 Bridge design.
