Improved Limit Equilibrium Methods for Evaluating the Shear Strength of Bimrocks During Bimtests

Nowadays bimrocks are widely used as a backfill material for artificial slopes and embankments, making the assessment of their shear strength properties a fundamental step for evaluating the stability of such structures. Improved 2-D and 3-D limit equilibrium methods, revised with respect to previous studies to account for the difference in the peak pushing horizontal forces during the two loading cycles of the test, were applied to revise the assessment of shear strength parameters of some bimrocks during bimtests carried out in 2011. The number of sections required in the 2-D method was determined on the basis of the relative errors of estimated strength parameters in comparison to those deriving from a 2-D analysis considering a very large amount of sections (i.e. 80 sections). The results show that neglecting the difference between the pushing horizontal forces recorded during the two loading cycles, as done in the previous researches, can produce relatively large errors in the back-calculated strength properties, especially for the cohesion term.