Shear Box Data Processing
The proposed method is demonstrated using results of DSB tests on a well-graded coarse sand with mean grain size D50=0.7mm in dense and loose condition. The samples were confined with vertical stress in the range of 20 to 160 kPa and sheared to a displacement of 8 to 10 mm.
Progressive Mobilization of Shear Strength
The variation of mobilized shear strength vs. the box displacements is shown for each normal stress in Figure 1a. A mobilized friction angle and cohesion for each corresponding displacement can be defined from these curves (e.g. Stematiu et al. 1991, Popescu 1993). First, from each t-d curve in Figure 1a and for each valuedi of the box displacement, a point is obtained in the t-s space (Figure 1b). Next, for each value of the box displacement, the mobilized friction angle and cohesion are estimated based on the Mohr-Coulomb criterion. Each Mohr Coulomb line can be considered as the instance yield surface in a t-s representation during the process of hardening and softening. The friction angle and cohesion obtained from these interpolation processes can then be expressed as discrete functions of the box displacement (Figure 1c) such as: