Boundary Wedges in two-dimensional passive soil failure

Earth pressure analyses which use a rigid-plastic Mohr-Coulomb soil model generally assume that all the soil within the rupture boundary is deforming and that the loading boundary stresses are fully mobilized. The analysis presented here shows that neither of these conditions is always realized and that zones of dead soil develop within the rupture boundary which alter the rupture surface geometry and interface stress conditions. It is shown that these zones of undeformed soil, called boundary wedges, are formed either because of kinematic constraints imposed by the motion of the interface or as a result of limitations imposed by interface configuration. A systematic method for predicting both the formation of these boundary wedges and their influence on interface stress conditions is presented. A calculation procedure, using dimensionless passive coefficients to supplement the charts of those coefficients already published, is set out. The theory proposed incorporates into the basic Sokolovski solution t...