Deformation and Stability Analyses of Hybrid Earth Retaining Structures

Abstract

Hybrid earth retaining structure (HERS) is an efficient solution for earth retention problems that face spatial constraints. Deformation and stability analyses of the HERS have not been studied rigorously. The present study focuses on the development of predictive equations for the estimation of maximum lateral facing displacement and global factor of safety of the mechanically stabilized earth (MSE) over the soil nail (SN) hybrid retaining (MSE/SN) wall, a category of the HERS. Multiple linear regression is performed using the method of least squares to develop the predictive equations. The regression models for the MSE/SN wall are proposed using the data generated from the finite element model of the MSE wall of heights 6, 8 and 10 m. The adequacy of the predictive equations is verified by evaluating the summary of fit statistics. The failure surface of the MSE/SN wall consists of two parts: (i) a linear surface which propagates internally through the bottom nail of the SN wall starting at the toe of the MSE/SN wall and propagates externally through the remaining height of the SN wall, and (ii) continuation of the linear surface externally behind the reinforcement through the MSE wall. It is concluded that the predominant deformation modes are base sliding, rotation about the base and local bulging of the MSE wall. The failure surface always passes through the soil nails and therefore, it is recommended that the ultimate pullout capacity of the nails should be assessed during the design of the MSE/SN walls.