Slip-Line Solution for the Active Earth Pressure of Narrow and Layered Backfills against Inverted T-Type Retaining Walls Rotating about the Base

In this research, we used a slip-line method for a typical failure mechanism simulated with adaptive finite-element software to investigate the active earth pressure of narrow and layered backfills against inverted T-type retaining walls rotating around the base mode. The slip-line field calculation models for the inverted T-type retaining wall with narrow and layered backfills were established considering the effect of the heel bottom plate and the inverted T-type retaining wall characteristics. Subsequently, the limit equilibrium and finite difference methods were used to solve the stress state of each point. The earth pressure acting on the stem and the second failure surface can be obtained by converting the boundary conditions. The proposed method was verified by comparing its results with those from finite-element limit analysis and existing theoretical solutions. Furthermore, several extensive parametric studies have investigated the effects of backfill width, heel length, and interface strength. The results show that increasing interface strength and decreasing backfill width help reduce the earth pressure against the stem and second failure surface. The change in the length of the heel bottom plate exhibited a dual effect.