Distinct element method simulations of rock-concrete interfaces under different boundary conditions

The shear behaviour of concrete-rock interfaces has been the aim of extensive research in geotechnical engineering applications such as rock socketed piles, rock bolts and concrete dam arch bridge foundations. Several experimental studies through direct shear tests have been conducted to evaluate the shear behaviour of rock concrete interfaces under CNL (Constant Normal Load) and CNS (Constant Normal Stiffness) conditions. In this paper, PFC2D numerical simulations of unbonded rock-concrete planar and saw-tooth triangular joints under CNL and CNS boundary conditions are conducted using the Shear Box Genesis (SBG) approach proposed by Bahaaddini et al. (2013b). The numerical simulation results are compared with experimental data published by Gutierrez (2013) and Gu et al. (2003). Results indicate that the SBG approach reproduces suitably the shear behaviour, failure mode and asperity damage of unbonded (planar and triangular) rock-concrete interfaces, specially under CNL conditions.