Passive earth pressure of narrow cohesionless backfill against inclined rigid retaining walls under translation mode

Abstract

In engineering applications, narrow backfills are often squeezed by retaining walls. Insufficient information is available with respect to the passive earth pressure, whereas the active earth pressure of narrow backfills against retaining walls has been considerably investigated. In this study, the passive failure mechanism of a narrow cohesionless backfill under translation mode has been investigated via a finite element lower-bound limit analysis, considering the effect of backfill geometries and external friction on the failure mechanism. Multiple-slip surfaces could be observed in a narrow backfill in the passive limit state. Further, we summarized the number of slip surfaces under various conditions and proposed a fitting function for the inclined angles of the slip surfaces. In addition, a multiple-slip surface calculation mode was developed. Subsequently, a method was derived for calculating the passive earth pressure of a narrow cohesionless backfill using the differential slice element method, the wedge limit equilibrium, and the finite difference method. Parametric studies explored the effects of the backfill geometries and internal and external frictions on the passive earth pressure. The results demonstrated an increase in the passive earth pressure and the number of slip surfaces when the backfill space decreased, in which the passive earth pressure was nonlinearly distributed.