A Numerical Model for the Bearing Capacity of Anchoring Interface in Composite Rock Mass by A Modified Nonlinear Bond-Slip Model

To investigate the mechanical behavior for rock bolt embedded in composite rock mass, a modified nonlinear bond-slip model considering the residual strength is established, and then a numerical model of composite rock mass is proposed. The modified nonlinear bond-slip model and the numerical model are verified by comparing with pullout test data, which show excellent performance in explaining and predicting the pullout response of rock bolt embedded in composite rock mass. The results show that the bearing capacity of anchoring interface in hard rock stratum is obviously better than that in soft rock stratum under the same anchoring length. The axial force and interfacial shear stress distribution curves have an obvious inflection point and mutation point at the rock strata interface. The axial force decays faster in hard rock stratum than that in soft rock stratum. The modified nonlinear bond-slip model and the numerical model improves the understanding of the mechanical mechanism for rock bolts embedded in composite rock mass.