Optimal design of Reinforced Concrete Cantilever Retaining Walls considering the requirement of slope stability

Abstract

A Reinforced Concrete Cantilever Retaining Wall (RCCRW) is one commonly used soil retaining structure in engineering practice. Various optimization techniques to obtain the optimal design of cantilever walls have been proposed, where the three basic geotechnical constraints of overturning, sliding and bearing failures have generally been taken into consideration. However, none of these approaches have considered the geotechnical requirement of slope stability. In this paper, a novel formulation for the optimal design of RCCRWs that considers the more complete requirements of geotechnical stability of overturning, sliding, bearing and slope failures, is described. The objective function of the minimum cost of materials, geotechnical constraints of wall failures (overturning, sliding and bearing) and the structural requirements for steel reinforcements in the wall sections all followed the conventional approaches used in previous works. Using the Ordinary Method of Slices (OMS) with a circular arc failure surface (CAFS), the factor of safety against slope failure (FSOMS) for a RCCRW was implicitly derived. Constraints for ensuring that the minimum FSOMS was higher than the required factor were enforced in the formulation. Design variables were the dimensions of the wall sections, corresponding steel reinforcements and the x-y coordinate of center of the CAFS, where the latter are the additional unknowns in this novel formulation. Computational performance of the proposed optimization method is demonstrated and verified through its application to the optimal design of two examples of RCCRWs.