A plastic-damage cohesive zone model for shear rupture band in geomaterials under mixed-mode and cyclic loading

The characterization of the mechanical behavior of the shear rupture band is essential to the analysis of the strain localization failure of geotechnical structures, with a key focus on describing the plastic-damage behavior and dilatancy of the geomaterial. A novel plastic-damage cohesive zone model is presented based on the unified plastic-damage modeling framework, in which an enhanced dilatancy angle evolution law is put forward to capture the dilatancy, and the yield function and the dissipation potential function are proposed to account for the tension/compression-shear coupling effect. The capability of the proposed model is demonstrated by its constitutive responses under several typical monotonic and cyclic loading paths, and further validated by simulating three laboratory tests of rock joint and silt-steel interface. The notable agreement between the simulation results and their experimental counterparts illustrates the effectiveness of the proposed model in characterizing the mechanical behavior of the shear rupture band under mixed-mode and cyclic loading conditions, including post-peak hardening/softening, plastic-damage behavior, and hysteresis.