Abstract
The progressive failure and scale effect of trap-door problems were evaluated, by comparing experimental results with finite element analyses employing the elasto-plastic model including the shear band effect. The experiments were performed in passive and active mode by measuring load-displacement relationships and observing shear band developments using two sizes of apparatus (the trap-door width of the smaller one was 5 cm and of the larger one 10 cm.) The load was measured with soil stress measurement cells embedded in the face of the trap-door. The shear band developments were observed using thin horizontal colored sand layers placed in the sand mass. The distribution of earth pressure by finite element analysis achieved good agreement with experimental results. The localized narrow zone of shear strain by the analysis was approximately identical with the observed shear band in both passive and active modes. The scale effect was recognized by the analysis and the experiment only in passive mode.
