Active earth pressures against rigid retaining walls with narrow cohesive backfill

In the case of a retaining wall adjacent to an existing basement or a vertical rock face, the width of backfill is limited. So it is not appropriate to use the Coulomb or Rankine theory to calculate the active earth pressures on the retaining wall. The software ABAQUS is used to execute the numerical simulation of active earth pressures on the rigid retaining wall with narrow cohesive backfill. The critical depth of the vertical cracks and the slip surfaces in the backfill are discussed. Based on the numerical analysis results, a new theoretical model is presented considering the adhesion between the wall and the fill as well as the vertical cracks in the fill. The formulae of the resultant force coefficient and the distribution of the active earth pressures on the retaining wall are put forward. The comparison between the theoretical and the numerical results demonstrate the rationality of the proposed theory. It is shown that the vertical cracks will appear at both sides of the fill, and the critical depth of the cracks, which do not change with the fill width, is approximately equal to the magnitude obtained by the Rankine theory. It is also shown that the one or multiple slip surfaces will occur in the fill as the width of the fill decreases. Furthermore, the active earth pressures on the retaining wall will decrease gradually from the magnitude obtained by the generalized Coulomb theory, which is based on the semi-infinite boundary assumption, to zero when the width of the fill decreases continuously. |