Limit Equilibrium Analysis Considering Deformation of Shear Band in Model Slope

摘要

The safety factors of the current design codes relating to soil structures don't always provide absolute and objective indices. In order to investigate the cause of this limitation, tilting failure tests of sandy soil model slopes and Bishop's simplified method were performed under three confining conditions at the toe of the slope. We introduced new strength parameters, c_γ and φ_γ, which are functions of shear strain γ. The limit equilibrium analysis using the values of c_γ and φ_γ corresponding to shear strains distributed in the shear band can explain well the actual failure mechanism of a model slope in every case of the three confining conditions. These results strongly suggest that the limitation of the safety factors stated in the first sentence might result from such an over-simplified failure mechanism as a priori introduction of a slip surface, which means "a simultaneous failure" all over the slip surface.