Active earth pressure for retaining structures in cohesive backfills with tensile strength cut-off

Abstract

The Mohr-Coulomb failure criterion, which is typically used to represent soil strength, has been found to overestimate the tensile strength of most soils. Considering this fact, the concept of tensile strength cut-off was adopted to reduce or eliminate the tensile strength from the criterion. Based on that concept, this study proposes a kinematical framework for the estimation of active earth pressure on retaining structures in cohesive backfills. According to the associative flow rule, a valid rotational collapse mechanism is established. The resultant active earth pressure is determined from the work rate balance equation and is expressed as a dimensionless active earth pressure coefficient. The proposed approach is validated by a numerical simulation. Design charts are presented for a parametric study and for simple use in engineering. The results show that the presence of soil cohesion has a favorable influence on the stability of retained soil masses. Accounting for the impact of tension cut-off leads to a more conservative result, and this impact tends to be more obvious with the increase of cohesion. Finally, the assumptions that were made about the validity of the associative flow rule and the action point of the resultant earth pressure are discussed.