Inclined Slice Method to Earth Pressure of Narrow Cohesionless Backfill against Rigid Walls under Various Displacement Modes

Abstract

The displacement modes of retaining walls in engineering are complicated, and the backfill behind retaining walls is often narrow. Failure mechanisms of soils under various displacement modes of retaining walls have not been clarified yet in previous studies. According to results of the finite element limit analysis, multiple sliding surfaces were observed developing reflectively between interfaces on both sides in the active limit state. In rotational displacement modes, some layers of soil near the rotated point maintained in the non-limit state which was not considered in the previous studies. Based on numerical analysis results, failure wedges were divided into differential soil slice elements by an inclined slice method. An analytical model was established to estimate the earth pressure of the narrow backfill under various displacement modes using the limit equilibrium method. The calculated results are consistent with the data gathered from previous tests. Compared with previous studies, the proposed method can reflect failure mechanisms of the narrow backfill and be adapted to various displacement modes of the retaining wall. The accuracy of the calculation results is high in the non-limit state soil layer. In addition, the boundary criterion between the narrow and semi-limit backfills was determined. Based on extensive parametric studies, it can be concluded that increasing the soil-wall interface friction and decreasing the backfill area would be conducive to decreasing the earth pressure and the depth of resultant application point.